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McG > Quiz 4 > Flashcards

Quiz 4 Flashcards

1
Q

what part of the oligo is labeled

A

5’ end

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2
Q

what is a “probe” in northern blotting

A

the 18-25 nt that is complimentary to a sequence on the mRNA in question and gets labeled with a radioactive phosphate. This allows visualization of the mRNA containing the target sequence

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3
Q

why are nuclei removed in northern blotting

A

to avoid contamination of the pre-mRNA

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4
Q

how is cytoplasmic mRNA isolated

A

taking advantage of the polyA tail that is only on mRNA and hybridizing it to an oligo(dT) tract on a column.

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5
Q

what is the bulk of cytoplasmic RNA

A

rRNA and tRNA

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6
Q

what does northern blotting allow you to do

A
  1. quantitate transcript levels
  2. determine whether gene induction is at the transcription level
    3 .detect changes in the size of a specific mRNA
  3. detect alternative splicing
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7
Q

why can northern blot give quantitative information about the level of expression

A

because the amount of probe that will bind is a function of the target molecules

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8
Q

what is the goal of PCR

A

make large quantities of a specific piece of DNA

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9
Q

where does PCR reaction add nucleotides

A

at the 3’ OH end

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10
Q

when do you get a copy of desired DNA sequence in PCR

A

after three reactions

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11
Q

temperature set points in PCR

A

Denaturing: 95 degrees C
extension (thermoresistant DNA polymerase extends from 3’): 72 degrees C
Annealing: 50-60 degrees C

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12
Q

why do we use PCR

A

detection of carrier for genetic diseases, single nucleotide polymorphisms (SNPs)

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13
Q

what is the result of SNPs (single nucleotide polymorphisms)

A

can put you at increased risk for disease but usually won’t actually CAUSE a disease in the way that a mutation would

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14
Q

PCR for RNA target method

A

use reverse transcriptase (RT) to convert mRNA into cDNA copy and this becomes substrate for PCR. Can use this instead of northern blot in some cases

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15
Q

advantage of real time PCR

A

include reaction dye like SYBR green which fluoresces when it binds double stranded DNA. Originally amount of input DNA is too low to be detected but will fluoresce as it progresses.

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16
Q

origin firing

A

initiation of DNA replication from a single origin

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17
Q

processivity

A

once polymerase binds, doesn’t detach for hundreds of thousands of nucleotides

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18
Q

ORC

A

origin recognition complex - it is what attaches to ori and recruits additional proteins that will recruit replication machinery.

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19
Q

how does DNA synthesis proceed

A

from a pre-existing primer that provides a 3’ OH where DNA polymerase can add the next nucleotide.

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20
Q

DNA primase

A

subunit of DNA polymerase alpha - RNA polymerase that lays down the RNA primer which is then extended by DNA polymerase

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21
Q

what is the issue with DNA using an RNA primer

A

can’t have RNA in the DNA – they need to be replaced and then the DNA needs to be ligated.

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22
Q

what cleaves off the RNA primer

A

FEN1, a flap endonuclease

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23
Q

function of DNA ligase

A

seals “nick” between 5’ end of old Okazaki DNA and 3’ end of “new” okazaki DNA.

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24
Q

types of DNA polymerase

A

epsilon: synthesizes leading strand
delta: synthesizes lagging strand
gamma: synthesizes mitochondrial DNA
alpha: synthesis of RNA primer and primer extension to start replication

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25
Q

how are DNA polymerases kept on DNA template

A

protein clamp that gets loaded as soon as replication initiates.

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26
Q

how can viral DNA replication be inhibited

A

use of selective DNA polymerase inhibitors. EX: AZT in HIV doesn’t have 3’ OH onto which subsequent nucleotide can be added. this is a nucleoside analogue.

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27
Q

telomere

A

end of chromosome - TTAGGG sequence over and over

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28
Q

T loop

A

at telomere - DNA folds back onto itself as G rich strand folds back and anneals to C rich strand creating local displacement loop (D loop) resulting in T loop

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29
Q

what is the purpose of T loop

A

distinguishes telomere from from a broken DNA which would signal cell for apoptosis. This also prevents end to end joining of chromosomes.

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30
Q

shelterin

A

telomere repeat sequences bound by telomere specific proteins

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31
Q

end replication problem

A

very end of lagging strand could not be synthesized so would keep getting shorter and there would be an inability to form the T loop

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32
Q

telomerase

A

reverse transcriptase which carries its own RNA template that can extend the lagging strand.

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33
Q

do normal undifferentiated somatic cells have telomerase activity

A

no - therefore they can only undergo a limited number of cell divisions.

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34
Q

hayflick limit

A

normal undifferentiated somatic cells do not have telomerase activity and can only undergo a limited number of cell divisions

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35
Q

telomerase and cancer

A

reactivation of telomerase unchecked so cells will continue to divide unchecked.

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36
Q

damage to cells caused by

A
  1. intracellular rxns of hydrolysis
  2. methylation
  3. reaction oxygen species (ROS)
  4. skin cells via UV light
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37
Q

exonuclease

A

3’ to 5’ that cleaves out DNA

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38
Q

intrinsic exonuclease

A

part of DNA polymerase that will cleave out a mismatched DNA pair before continuing synthesis

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39
Q

if the intrinsic nuclease doesn’t catch the error, what will

A

the mismatch repair system - only degrades the one nucleotide area and adds a new one via DNA polymerase delta.

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40
Q

proteins in mismatch repair system

A

MLH and MSH

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41
Q

how does MMR system work

A

recognizes mistake, chews back from 3’ OH end at “nick”,, and then DNA polymerase will syntehsize a new, correct strand

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42
Q

what happens if a base is modified

A

modified bases can pair with the wrong base

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43
Q

what repairs modified bases

A

base excision repair

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44
Q

how does base excision repair work

A

glcolysases that recognize unnatural bases in DNA (ex: uracil glycolase) cut the bond between base and 1’C of ribose sugar to create an abasic site. Abasic nucleotide removed and correct nucleotide is filled in.

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45
Q

what happens to methylated bases in terms of repair

A

can be repaired by direct reversal wherein a protein binds to the methylated base and transfers the methyl group to a cys residue in its active site

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46
Q

what does UV cause

A

pyrimidine dimers - pyrimidine rings covalently link to each other causing a kink in DNA which blocks replication and txn

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47
Q

what deals with pyrimidine dimers

A

nucleotide excision repair system or translesion synthesis

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48
Q

what does the nucleotide repair system deal with and how does it work

A

pyrimidine dimers. XP protein recognizes distorted DNA region, other XP proteins unwind and excise this patch of DNA, filled in by DNA pol epsilon or delta

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49
Q

what is translesion synthesis

A

different DNA polymerases that are not processive and are error prone replicate past the pyrimidine dimer, either putting correct or incorrect bases opposite dimer.

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50
Q

why is translesion synthesis OK even though it adds incorrect bases often

A

disadvantage of an incorrect base is far outweighed by the disastrous effect of a block to replication that would occur if there was no repair and translesion synthesis.

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51
Q

what causes double stranded DNA breaks

A

exposure to x-rays

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52
Q

how are double stranded breaks usually repaired

A

non homologous end joining (NHEJ) or homologous recombination

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53
Q

explain NHEJ

A

involves imprecise ligation of broken ends

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54
Q

explain homologous recombination

A

the other chromosome copy is used as the basis of repair for the broken one

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55
Q

what is BRCA2 involved in

A

encodes a protein used in repair via homologous recombination

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56
Q

what proteins are involved in NHEJ

A

Ku and Kinases

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57
Q

how does homologous recombination work

A

RAD proteins allow single stranded DNA chromosome and repair.

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58
Q

when does homologous recombination work

A

in S phase and G2 because need another copy so cell needs to be in active division

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59
Q

what causes hemophelia A

A

recombination event leading to inversion of a chromosomal region

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60
Q

what catalyzes transposition

A

transposase enyzme

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61
Q

what encodes the transposase enzyme

A

a gene located on the transposon itself

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62
Q

types of transposons

A

simple: nothing but transposase coding sequence
complex: has some other gene (ex: antibiotic resistance)

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63
Q

prokaryotic transposons vs eukaryotic transposons

A

prokaryotic: DNA - through plasmids etc
eukaryotic: through RNA intermediate - DNA sequence transcribed by RNA polymerase, creating RNA copy. Reverse transcriptase converts this RNA to double stranded DNA which then integrates into target DNA via integrase protein.

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64
Q

where is the coding sequence for reverse transcriptase in terms of eukaryotic transposons

A

the retransposon sequence

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65
Q

LINES

A

long interspersed elements - 500,000 of them, termed L1. full thing is 6000 bp long but usually truncated or mutated and non functional.

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66
Q

what is the function of L1

A

code for a protein that has reverse transcriptase activity

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67
Q

SINES

A

short interspersed elements

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68
Q

what is the main SINE

A

Alul - 300 bp that is present in 1 million copies. No coding sequence (IN INTRON!!)

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69
Q

what does transposition of Alul depend on

A

L1 element

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70
Q

VNTR

A

variable number of tandem repeats - repeated sequences in contiguous copies. different individuals have different number of repeats. can use PCR analysis and this to do forensic ID

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71
Q

what are proteins held together by in their natural state

A

multiple weak hydrophobic interactions - can also have some disulfide bonds

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72
Q

why don’t proteins self assemble in the cell without any help

A

over crowding and high temperature

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73
Q

what happens instead of folding in a normal cell if no helpers

A

proteins aggregate instead of folding

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74
Q

3 phases of folding

A
  1. burst (0-5 ms): formation of secondary structure and collapse of hydrophobic core
  2. intermediate phase (5-100 ms): involves formation of molten globule intermediate, which has characteristics of both folded and unfolded proteins. (secondary structures finding each other)
  3. Protein folding and attainment of native structure (rate limiting): conversion of the molten globule via global repacking of hydrophobic side chains and association of domains that were folded independently in intermediate phase
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75
Q

molecular chaperons

A

proteins that bind and stabilize otherwise unstable conformer of another protein and facilitate its correct fate in vivo

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76
Q

what can molecular chaperones help with

A
  1. folding
  2. oligomeric assembly
  3. transport to a particular subcellular compartment
  4. controlled switching between active and inactive conformations
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77
Q

how do molecular chaperones bind and release proteins

A

dependent on ATP binding, hydrolysis and nucleotide exchange.

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78
Q

are molecular chaperones enzymes

A

NO! bind weakly to hydrophobic AA - they increase the yield but not the rate.

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79
Q

structure of chaperones

A

7 small subunit lid, two 7 subunit barrels stacked on eachother

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80
Q

how do proteins get inside chaperonin

A

unfolded proteins bind to rim of barrel and are displaced into cavity by the lid structure. Protein can then fold in sequestered environment of the chamber. Lid dissociates due to changes in conformation of large subunit as ATP is hydrolyzed.

81
Q

what is chaperone gene transcription controlled by

A

Hsf which responds to presence of unfolded protein or heat shock or other types of proteotoxic stress

82
Q

what is protein degradation in the cytosol and nucleus mainly accomplished by

A

proteasome: a large, gated protease

83
Q

how to proteasome substrates get to proteasome

A

covalent linkage to multiple copies of ubiquitin

84
Q

proteasome structure

A

central catalytic core and regulatory cap - acces to core via tunnel formed at the ends of alpha subunit rings

85
Q

what enters proteasome

A

single unfolded polypeptide - degraded processively

86
Q

three activities of eukaryotic proteasomes

A
  1. cleaves after hydrophobic AA (like chymotrypsin)
  2. cleaves after basic AA (trypsin)
  3. cleaves after acidic AA (peptidyl-glutamyl peptide hydrolyzing activity)
87
Q

what are the two add’l activities of mammalian proteasomes

A
  1. cleave after branched AA

2. cleave between neutral AA

88
Q

what does the regulatory complex of proteasames recognize

A

ubiquitinylated substrates

89
Q

ubiquitin

A

protein that becomes covalently linked to polypeptides that are substrates for degradation

90
Q

where does ubiquitin link

A

in linear chains where the carboxyl end of the terminal glycine becomes covalently attached to epsilon amino group of lysine 48.

91
Q

what does attachment of ubiquitin require

A

action of E1, E2, and E3

92
Q

function of E1

A

carries out ATP dependent activation of C terminal glycine in two step rxn

  1. ubiquitin adenylate formed (dissociated anion)
  2. transfer of activated ubiquitin to thiol site in E1 (S-H bond)
93
Q

function of E2

A

ubiquitin conjugating enzyme - accept ubiquitin from E1 and transfer it to the protein substrate in a reaction that requires E3
*essentially catalyzes reaction of transferring UB to substrate

94
Q

function of E3

A

ubiquitin protein ligase - specifies substrate selection

95
Q

how are misfolded proteins identified

A

molecular chaperones and then targeted to specific ubiquitin ligases.

96
Q

CHIP

A

C-terminal Hsp Interacting Protein: binds directly to Hsp70 and catalyzes ubiquitinylation of misfolded proteins

97
Q

aggresome

A

aggregated proteins that are meeting point for molecular chaperones and proteasomes

98
Q

when do aggregates occur and why

A

when misfolded proteins overwhelm the ubiquitin/proteasome pathyway - keep them together and secluded so that they don’t damage the cell

99
Q

what are aggregates bound together by

A

hydrophobic interactions or ordered assemblies of amyloid fibres

100
Q

what clears aggregates

A

autophagic system as they are inaccessible to proteasome

101
Q

amyloid

A

conformation of proteins that involves a stacked beta sheet - form fibres that are very stable

102
Q

alzheimers disease

A

extracellular amyloids of a alpha-beta peptide cleaved from alzheimer’s precursor protein.
intracellular deposits or neurofibrillary tangles, of the microtubule binding protein, tau that is hyperphosphorylated

103
Q

tau

A

microtubule binding protein – can form aggregates in alzheimer’s – there are hyperphosphorylated

104
Q

parkinson’s disease

A

loss of dopaminergic neurons in substantia nigra - aggregates enriched in alpha-synuclein (lewy bodies)

105
Q

polyglutamine repeat disease

A

over 36 glutamine (Q) residues - can cause huntington’s disease among others

106
Q

function of smooth ER

A

synthesis of lipids, cytochrome P450 to detox in liver

107
Q

function of rough ER

A

many ribosomes

108
Q

chemical environment inside vs outside cell

A

extracellular is oxidizing, intracellular (cytosol) is reducing

109
Q

how are newly made proteins targeted to the ER membrane

A

N terminal signal peptide - enriched in hydrophobic AA and is often cleaved after import into ER though sometimes there is internal targeting sequence that doesn’t get cleaved

110
Q

what does the signal peptide bind to

A

signal recognition particle (SRP), attaches while protein is still being translated

111
Q

how does SRP works

A

samples newly made proteins, finds right one, attaches while still being translated and arrests translation. Binds to ER via an SRP receptor complex which is adjacent to translocon.

112
Q

transolocon

A

aqueous channel where SRP and protein complex binds. Now TLN can happen into ER itself

113
Q

how does translocon open

A

into membrane itself (sideways) for membrane proteins or goes through membrane vertically

114
Q

what do proteins that require disulphide bonds req

A

disulphide isomerase (these bonds are frequently in proteins outside the cell)

115
Q

prolyl isomerase

A

helps folding

116
Q

what is added to proteins entering the ER

A

glycosylated on aspargine (N linked) via 14 residue carb with mannose, glucose, and N-acetyl-gucosamine.

117
Q

where is the glycosylated complex from

A

dolichol anchor to substrate protein

118
Q

calnexin

A

binds to glucose residues on protein in ER until it folds, then it dissociates

119
Q

what is glycosylation important for

A
  1. protein folding
  2. protein stability
  3. outside of cell can act as recognition complex
120
Q

Type I and Type II membrane proteins

A

1: N terminus in lumen of ER
2. C terminus in lumen of ER
OR topologically complex with membrane spanning regions

121
Q

phases of the quality control pathway

A
  1. activation of signaling pathway called unfolded protein response (UPR)
  2. ER associated degradation (ERAD)
122
Q

UPR

A

expression of genes that encode ER specific molecular chaperones and components of the ubiquitin/proteasome pathway so they can be destroyed.

123
Q

ERAD

A

luminal and membrane proteins are retrotranslocated from the ER to the cytosol for degradation by the proteasome. (Can’t happen in the ER!).

124
Q

when can ERAD have expression increased

A

during UPR

125
Q

Golgi structure

A

flat membranous discs stacked with curved appearance

126
Q

what happens to proteins once inside the golgi

A

modified by post tln modification

127
Q

two ways of moving in golgi

A
  1. vesicular transport: sequentially in vesicles that go to each stack
  2. cisternal maturation - stacks constantly moving. enzymes are what move back
128
Q

how do ER proteins mistakenly in golgi get back

A

receptor recognizes special peptide sequence (KDEL) at C terminus of ER proteins that escaped to golgi - returned to ER after interacting with receptor

129
Q

how are lysosomal enzymes delivered to lysosome

A

by secretory pathway - identified in cis golgi by an enzyme that phosphorylates a specific mannose residue of the core carb that was added in the ER (mannose -6-phosphate) Recognized in trans golgi by M6P receptor that sequesters enzymes into specific vesicle for transport to lysosome

130
Q

importance of pH in lysosome

A

M6P binding at pH 6 in TGN. Removal of phosphate makes pH 5 - end up with two vesicles, one with receptors and one with cargo that gets delivered to lysosome which has a pH of 5

131
Q

pro region

A

on peptide hormones, trimmed before enzyme becomes active.

132
Q

why do lysosomes look big in lysosomal storage diseases

A

distended because missing enzymes, not because theyre storing extra stuff

133
Q

what is iron bound to when it comes into the cell

A

transferrin

134
Q

what is cholesterol endocytosed via

A

LDL receptor

135
Q

structure of LDL

A

vesicle contains cholesterol, has phospholipid/cholesterol coat, and ApoB100 protein that is what interacts with the receptor

136
Q

function of clathrin, COPI, COPII

A

clathrin: TGN to PM or endosomes/lysosomes
COPII: ER to golgi
COPI: golgi back to ER in retrieval pathway

137
Q

what pinches clathrin vesicles off and how can action be inhibited

A

dynamin - can be inhibited by inhibiting ATPase

138
Q

what actually happens to the clathrin coats that make them bud out

A

polymerize

139
Q

what does clathrin bind to

A

adaptin (AP1 or AP2) in the cytosol

140
Q

why must the coat disassemble after being pinched off

A

THIS is how the targeting happens

141
Q

how do proteins attach to target membrane

A

RAB proteins attach to tethering proteins

142
Q

RABs

A

small GTP binding proteins that bind to vesicles and perform a proof-reading function by interacting with specific tethering proteins on target membrane

143
Q

SNARE proteins

A

target but mostly fuse membranes together

144
Q

how do SNARE proteins work

A

v-snare (vesicle snare) interacts with t-snare (target membrane snare). These come together and wind and help overcome energy barrier of hydrophilic head groups + water with hydrophobic hydrocarbons. Squeeze out water which decreases energy of interaction.

145
Q

how do SNARE proteins disassemble

A

fusion with a specific chaperone, NSF. Needs to be specific because SNARE energy of interaction is so low.

146
Q

how do proteins get moved in and out of the mitochondria

A

TOM proteins bring them in the outer membrane, TIM proteins are on the inner membrane and bring it in

147
Q

permeability of inner membrane in mitochondria

A

impermeable

148
Q

what is the cristae rich in

A

enzymes that form ATP from ADP

149
Q

what is in the intermembrane space

A

enzymes that phosphorylate other nucleotides apart from ADP

150
Q

function of the matrix

A

mainly oxidative - contains the mitochondrial genome, ribosomes, tRNAs, and molecular chaperones for folding

151
Q

what does the mitochondrial genome code for

A

subunits of components of respiratory chain

152
Q

how are mitochondrial proteins targeted

A
  1. 15-35 residue N terminal with basic AA that is cleaved in the matrix by an endoprotease
  2. non cleaved internal sequence
153
Q

how is TIM opened

A

the positive charge on the presequence and use of membrane potential.

154
Q

what is function of Hsp70 in mitochondrial import

A

binds the protein when it comes through TIM and pulls it into the matrix - helps it to fold

155
Q

LHON

A

leber’s hereditary optic neuropathy - mitochondrial missense mutation in subunit 4 of NADH-coQ reductase. Present at midlife with sudden blindness. SAME mutation can lead to dystonia which is generalized motor disorder.

156
Q

peroxisome

A

small single membrane organelles that get their name from metabolism of hydrogen peroxide of organalle. important for fatty acid beta oxidation and plasmalogen synthesis (

157
Q

what is hydrogen peroxide metabolized by in peroxisome

A

catalase - makes it into water and oxygen

158
Q

what are peroxisomal proteins encoded by

A

nuclear genes - imported post TLN in FOLDED state into organelle (different than mitochondria which is unfolded)

159
Q

zellwegers syndrome

A

no import of peroxisomal enzyme

160
Q

ALD

A

oxidation of long chain fatty acid is defective - this gene is a membrane transporter for long chain fatty acyl coA synthase from cytosol to peroxisome matrix

161
Q

what is the function of RNA pol II

A

transcribes ribosomal protein genes

162
Q

NLS

A

nuclear localization sequence - can exist anywhere on the protein but must be accessible to receptors. 4-8 AA rich in arg and lys. DONT GET CLEAVED!!!

163
Q

NES

A

type of localization sequence - exit signal, there are also import signals.

164
Q

mechanism of nuclear transport depends on

A

karyopharins

165
Q

karyopherins

A

recognize NLS or NES sequences. Karyopherin binds RanGTP when it enters the nucleus and unloads cargo, this gets cleaved to GTP to GDP when it exits alone with receptor.

166
Q

GAP

A

GTPase activating protein - cleaves GTP to GDP

167
Q

structure of IF

A

elongated and alpha helical with globular N terminus and globular C terminal tail. Forms a dimer that is a coiled coil, associate to form a staggered tetramer. 8 tetramers assemble to make filament.

168
Q

IF proteins

A
  1. keratins
  2. vimentins/desmin
  3. neurofilaments
  4. nuclear lamins
169
Q

what causes ALS

A

abnormal accumulation of neurofilaments in axon and cell body or motor neurons

170
Q

what kind of IF can disassemble

A

nuclear lamins - usually can’t disassemble but these get phosphorylated in the cell cycle which allows them to

171
Q

MT

A

long, hollow tubules - intracellular organization and transport.

172
Q

what do MTs form

A

mitotic spindle, cilia, flagella.

173
Q

why do MTs have polarity

A

because dimers prefer to bind to exposed B tubulin surface than alpha tubulin in profilament.

174
Q

where is the + and - end of MTs

A

+ is beta (this is where it grows!) - is alpha

175
Q

what stabilizes MTs

A

microtubule associated protein

176
Q

when does B tubulin hydrolyze bound GTP

A

when tubulin dimer binds to an MT - when there are plentiful free dimers, hydrolysis occurs after further tubulin is added

177
Q

how do MTs pull chromosomes apart

A

dynein like motor proteins on cell membrane, kinesin binds to overlap and pulls, also get dynamic instability at kinetochore

178
Q

dynein vs kinesin

A 
kinesin = + end directed
dynein = - end directed
179
Q

what is wave action of cilia and flagella propagated by

A

dynein - gets translated from one to the next

180
Q

how does force generation of actin occur

A

polymerization and in conjunction with myosin motor proteins

181
Q

treadmilling

A

in regular cells, actin isn’t fixed and the rate of addition at one end is the same as the rate of degradation at the other

182
Q

lamellipodia

A

actin polymerization pushes the cell membrane out and this extension is the lamellipodia

183
Q

filopodia

A

during movement via actin when it is polymerizing and pushing out

184
Q

four types of cell adhesion molecules

A
  1. cadherins
  2. the Ig superfamily
  3. integrins
  4. selectins
185
Q

what makes up tight junctions

A

claudins and occludens

186
Q

types of anchoring junction

A

adherens, desmosome, hemidesmosome

187
Q

adherens junctions

A

has to do with homophilic interactions between cadherins. binds to receptor inside cell that then binds to actin. makes big connections of actin via alpha and beta catenin

188
Q

desmosome

A

bind together on inside of cell and link together with IF

189
Q

hemidesmosome

A

link together ECM with cell - protein that does linking is integrin. Binds to IF or actin in the case of focal adhesions

190
Q

integrins

A

cell matrix receptors on cells - abundant on surface and bind ligands with low affinity. alpha and beta subunits held together non covalently.

191
Q

selectins

A

lectins (carb binding) that mediate calcium dependent cell cell adhesion in the bloodstream. during inflammation, endothelial cells express E selectin that binds to the carbs on white blood cells and platelets (which have L and P selectins)

192
Q

BL

A

basal lamina - prevents passing of macromolecules from blood to urine. Prevents fibroblasts from contacting epithelial cells. Does NOT stop macrophages, lymphocytes, and nerve processes from passing through it

193
Q

ECM components

A

GAGs which are usually bound to protein cores to form proteoglycans. also made up of laminin, collagen, fibronectin, and elastin

194
Q

Marfans syndrome mutation

A

in fibrilin which is part of elastin. usually bound to TGF beta in inactive form but with mutation it isnt so TGF beta is overactive. a lot of growth factor causes the disease

195
Q

fibronectin

A

modular protein that binds to other matrix molecules and receptors on cells. binds to integrin in the cell.

196
Q

anchorage dependence

A

most cells need to attach for growth and survival - proliferate better when attached and spread out.

197
Q

proteases

A

break down the matrix which is important for cell migration

198
Q

how are proteases inhibited

A
  1. local activation (need to be activated by other proteases)
  2. confinement by cell surface receprots
  3. secretion of inhibitors

McG (11 decks)

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