S4 Flashcards
cell expression basic concept for N and E cadherin
can sort by type or by level of cellular expression
cell adheisoon molecuels vs cell junctions
membrane proteins vs aggregates of transmembrane and intracellular proteins
inuitive complexity, size, transience and stability differences
epithelial tissue
mechanical stress cell to cell by cytoskeletal filaments
anchored to cell matric and cell to cell adhestin sites
connective tissue
ECM directly bears mechanical stress
metastasis
cells leave tumor then enter blood stream then extravasation to new tissue to colonize
neural development and adhesion
cells in epitheliem and then lose adheision when dividing then adhere to radial glia to move up
anchoring junctions
actin filament attacchment sites
intermediate filament attatchment sites
actin filament attatchment sites
cell cell junctions (adherins junctions)
cell matrix junctions (actin linked cell matrix adhesions)
intermediate filament attatchment sites
cell cell is desmosomes
cell matrix is hemidesmosomes
Occluding junctions
tight junctions in vertes
septate in invertes
signal relay junctions
chemical synapses
immunological synnapes
transmembrane lignad - receptor and cell cell signaling contancts
role of extra junctional adehesion molecuels
involved in forming junctions but not direcly part of it
ways to measure adhesion/junction force
centrifugation atomic force microsopy dual pippette assay flipping assay magnetic bead FRET
this section TEM vs Freeze fracture TEM
close vs overview?
freeze fracture
separate leaflits of PM
E face is smooth exoplasmic
P face is rough protoplasmic
occluding junctions on endothelim of intestings
tight junctions
apical
usually top down is tight,adherin, desomosomal, hemidesmosomal
visible as terminal bar
protein occludin
sealing strands with actin microfilaments
polarize cells
2 anchoring junction protein types
intracellular anchoring proteins
transmembrane adheision proteins (adheision molecuels)
adherins junction
cell to cell classical cadheirins bind to same on other cell actin filaments alpha and beta cateinn
desomosomes
non classiscal cadherines cell to cell bind desmoglein and desmocollin on other cell intermediate filaments plakoglobin
adherens and development
contract to create invaginations for like epithelial tube
E cadherins outside tube
N cadherins in the ring
mechanotransduction
when stretched more actin recruited
hemi vs desmosome
both link to intermediate
hemi to basal lamina,
desmo is cell cell
pemphigus vulgaris
autoimmune disease affecting desomosmes
antibodies disrupt in skin causing blisters, flfluid loss and infection
hemidesmosomes in EM
look like half desmosomes
anchor basal lamina to intermediate filaments
disrupted in bullous pemphigold
focal adhesions
link actin to ECM
cell movement and wound healing
integreins
integrin activation
ligand for outside in or tallin for inside out
Talin as a mechanotradducoer
vinculin binding site exposed from tension
intracellular
selectins
adhesion molecules that dont participate in junctions
transient adhesions
extravasation
weak adhesion and rolling (selectin dependent)
strong adhesion and emigration (integrin dependent)
white blood cells leave blood stream to chase inflammation
neurexin and neurolign
involved in cell cell connections at synapes and signaling for developing and maintaintng neural contacts
integrin receptor basics
membrane spanning
bind to ECM proteins
transduce bidirectionsally
GAGs
glycosamino glyicans
amino sugar
4 groups mainly hylauran
hylauronan
simples GAG
not bownd to core protein
proteoglycan
GAGs covalentlybound to core preotiens
gel like ground substances
functions of GAGS and proteoglycans
regulate chemical signaling
regulate other secreted proteins
act as co receptors
resist compressive force
hurlers syndrome
accumulation of the GAG heparan sulfate
deficincy in degration enzyme
fibrous proteins in ECM
collagen
elastic fibers
fibronectin
collagen
tensile strength
triple helix
hydoxyproline and hydroxylisine residues are critical for fibril formation
cells determine size/ organizaation via gene expression
types of collagen
I most comman for like skin and bone
IX and XII for link fibrils
IV network forming
VII anchorning
collagen assembly steps
syn of pro alpha chain hydroxylation of prolines and lysines glycosylation of selected hydroxylysines self assmbly of 3 pro alhpha chains procollagen triple helix formation via inter chain H bonds at hydroxylated residues secretion cleaveage of propetides self aseembly into crosslinked fibriles
fibril associated collagens
wickerwork is perpindicular
budneled is parallel
scurvy
vitamin C deficiency
no hydroxylation so no collagen
osteogeneis imperfecta
colllagen Type I mutated
weak bones
scleroderma
autoimmune scar tissue buildup and collagen in dkinand organs
elastic fibers
recoil after trasent stretch
elastin with loos random coil model
microfibril coat eleastin core as scaffold made of fibrillin
marfans syndrom
mutation of fibrilin gene
lense displacement, skin joints weird
predisposint ot aortic rupture
fibronectin
cell-ECM interaction specific binding sites for matrix macromleucles and cell surface receptors dimers with repeated domains Type III binds integrin at RGD sequence needs to bind integrin to form fibril
basal lamina
ECM under epithelial cells
laminin is primary component, cross shaped, cue from cell to form sheet
type IV collagen
basal lamina functions
mechanical support compartmentalize tissue selective filter scaffold migration cell polarity
epidermolysis bullosa
defece in basmemtn membrane leading to blisters
ECM turnover
remodleing matrix metalloproteasses serine proteases regulated by local activaaiotn cell surface receptors secreted inhibtiros protease specificity
integrin receptors
heterodimerice transmembrane ECM receptors alpha and beta subunites distinct dimers short C tails and large N heads Tail link integrin to cytoskeleton head to ECM proeins
receptor mediated signaling
dynamic
inactive - bent, tighlty folded heads, tail tail contact
active - separate tails, unfolded heads
outside in signaling
ligand binds head
makes active conformation exposing binding site on tail
talin binds beta subuinit and anchors integrin to cytoskeleton
inside out signaling
talin activated binds to Beta subunit creating cross talk on surface
allosteric regulation
ligan binding make conform change on both sides so bidirectional signals
basically cuz dimers, changes in one affects both
integrin clustering
receptors in high concentratin with low affinity for ligand
velcro principle: bunhch of weak make strong
activated integrins associate laterally
focal adheison
ECM binds integrins
downstream effects, no intrinsic kinase in integrins
focal adhesion kinase
binding site revealed when talin binds integrin
FAK gets activted
growth factor receptor regulation
direct is independent because GFRs cross phosphorylate
indirect is depended
leukocyte adhesion deficiency
Beta 2 deficient so WBCs cant get to infection
glanzmans disease
Beta 3
platelates cant clot ucz cant interact with fibrinogen
ECM-integrin cell morphology
spatial signals
agar for 2D layers but spherical in ECM for mammilary
mechanical signals bidirectionally
reciperocal communication btwn cells and environment
ECM-integrin cell survivial
biochemical cues integrins and GFRs anchorage dependent growth contact promotion detatchment and apoptosis
anoikis
cell death as resuld of ECM detatchment
cancer cells resist this
ECM-integrin and Migration
mechanical support and chemical cues dor dirceting
differential integrin activation for moving
ECM integrin dysfunction and cancer progressin
break through basal lamina
matrix protease activation
invadopodia are membrane protrutions
ECM integrin dysfunction and cancer
matrix stiffness
tumor progresssion
matrix not tumor is whats felt
LOX
inhibit this and increase collagen cross links
volociximab
against alha5beta
slows tumor growth
cilengitide
targets avb5 and avb 3
inner vs outter blastocyst
inner is animal, forms disc
outer forms placenta
3 germ layers
endoderm
mesoderm
ectoderm
gastrulation
endoderm - epeithelial cells
mesoderm - heart, muscles, bone
ectoderm - nervous system, epidermis
epithelial cell movmentn
out of mesenchymal loss of cellcell junctions lose apical basal polarity alpha SMA expression for front back polarity MMP upregulate
heart organogenesis
cardiogenic area near head u shaped primitive blood cells 2 tubes fuse bulbos folding and lifting into compartments controll of transcription factors by microRNA
lung organogenesis
tracheal buds then branching
surfactant
Tbx5, Wnt, Bmp
FGF and Shh to create branches
limb development
initiation has antiror Gli3 and Wnt and posterior Hand2 and Wnt
early secification has
ZPA with Shh posterior and AER distal with FGF
apoptosis to separate
teratology
study for birth defects
knockouts cool if they work in vivo but might be embyronically lethal and useless
in vitro fertilization
create permanant collections of embryonic stem cells
genetic engineernig steps
take special stem cells
inject in to blastocyst inner cell mass
implant in foster mother making chimeric mouse
Crispr Cas 9
dont need ES cells
can just inject DNA changes
stem cell stages
self renewal
specification
differentiation
specificatoin
make stem cells pic a path
autonomous - genome, asymmetric division not external factors
syncytial - unusual, nuculus not cytoplasm divides
conditional - environment: indirect with paracrinn Shh or integrines; direct with cell cell contact via juxtacrin or notch
differentiation
take specified scells and specialize them into cell type
key characteristics of stem cells
self renewal without loss of differntation potential
can make differentaited daughter cells
diabetes stem cell treatment
beta cell transplant
potency
number of possible fates
totipotency
can be anything
found in zygotes for 8 days
pluripotents
can make all embryo cells
in innerc cell mass till day 10
make teratoma in tumor in mice that hass all 3 germ layers
oct4, nanog, sox2
multipotent
all tissues of an organ
hematopoeitic for blood
mesenchymal for connective tissue
unipotent
one type
like spermatogonia
Lineage tracing
have reporter gene so can tell all the progeny of a single cell
stem cell niche basics
microenvironment and cells next to stem cells that support and tell when/how to divide
daugther cells divide away from niches so dont get SC signals
stem cells start doing stuff before niche is formed
drosophila stem cell niches male
male of SC have hub cells at apical end
attached side stays SC
unattached activates JAK STAT pathway to divide and differentiate
drosophila stem cell niche female
cap cells at apical end
signal through cadherin junctinos
TGF beta ligands promote MAD+P which turns off BAM but BAM is on in daughter cells and leads to differentation
intestinal stem cell niche
Lrg5+ at crytp base for rapid
Bmi1+ for slowly (further up)
alpi+ can dedifferentiate back to Lrg5+
neural stem cell niche
in V-SVz
serial transplantatio
take out tag culture put back regenerate organ
label retention
stem cells can turn off cell cycle to
damage repair
queiscent by NHEJ
cycleing by HR will have higher fidelity but also ROS so bad
plasticity of differentiatied cells
dedifferentiation to same lineage happens in instestines with Alpi+
trandifferentiation when daugter cells become multiple types (pancrease)
important for regeneration
lineage tracing
cre with stem cell promoter and a marker
mTor
nutreint sensing
related to insulin and insulin like receptors
senescence
cell lineage lifespan
defined by number of doublings
telomeres
hayflick limit
human cells do not spontaneously immortalize except for tumors
mouse cells do
3T3 cells
cells per square centimeter is 3x10^5
concentration where they immortalize but retain normal phenotype
SV40LT
viral protein
inactivates p53 and pRb
creates crisis and apoptosis but surviviors immortalize as tumors
papilloma virus
imortalizes by targeting E proteins
Li faumeni syndrome
heterozygous mutation for p53
p53 and sensecence
+P activates p53 which activates p21 and arrests cell cycle or activates PUMA and apoptosis
senscenes char that are opposite of apoptosis
maintain viablity cells persist secrete stuff pro inflame natural killer cell response impact tissues
4 triggers of p53 and senescence
telomere attrition
oncogenic activation
oxidative stress
mitochondrial stress
telomere attritions
end gets shorter cuz overhang and okaziki fragments
T loop stuff not able to recover full length
humans dont have telomerase
DNA damage once too short activated p53
oncogenic transformation
immortal cells with activated ras proteins become tumors but mortal ones senesce
pluiipotent blood stem cells
CD34+ and Lin Negative
1/1000 in bone marrow
neutrophil
most abundant granulocyte phagocitic line of defense against bacteria
basophil
least numerous
histamine and allergies
eosinophils
kill parasitic worms
monocytes
become macrophages in tissue
function of WBCs
innate non specific immune response
extravasation from blood stream to inflammation
lymphocytes
adaptive immune cels
make antibodies
B cells have antibody in membrane and makes more
T cells eat then present antigen to make more helpers and killers
chars of hematopoitic ontageny timing
mesoblastic 2 weeks to 2 months
hepatic 6 weeks to birth (liver and soome spleen)
myeloid - bone marrow red for intrauterine life
stromal cells
stem cells in niche bound to these stay stem cells otherwise differentiate
has kit ligand and SCF
early hematopoietic colony stimulating factors CSFs
stem cell factor SCF/kit ligand
IL-3 / multi csf
intermediate hematopoietic colony stimulating factors CSFs
lineage commitment
GM-CSF -> myelocytes
IL-7 -> lymphocytes
late hematopoietic colony stimulating factors CSFs
single lineage G-CSF -> neutrophils IL-5 -> eosinophils M-CSF -> monocytes/macrophages IL-4 -> mast cells EPO -> erythrocytes
red blood cell development
extrudes nuclesu with division
loses ‘dont eat me’ with age
oxygen does not stimulate ECO which makes sense cuz if theres less oxygen then you need more blood for efficiecny
counting precursors
cell surface makers tell where in process
cd34 early on
leukemia and lymphoma basics
mutation of white blood cells
philadelphia chromosome when 9 translocates with 22
stem cells
Acute L
blast form ready to divide
CD19 negative in B cell precusor
CAR T therapy
chimeric antigen receptors change T cell targets to CD19 postive
chronic leukemia
malignant
insidious
adult T cell LL
Rash
mycosis fungoides
invades skin then blood
multiple myeloma
IL6
infectino risk
Non hodgkin lymphoma
CD19
more frequent
Burkitt lymphoma
jaw
c-myc
CD20
hodkin lymphoma
lymph nodes
CD15,30
cytokines attract other cell types
antibody treatments inneffective
autosomal dominant
vertical pattern
think punnet square only one parent needs it and then theres a 50% chance regardless of gender
paternal age effect
autosomal recessive
horizontal cuz only one generation effected
heterozygous carriers
need two heterozygous parents to be affected
25% affected
25% no mutation
50% carrier
punnet square
Y chromosome inheretance
males only affected and transmitting
mitochondrial inheretance
miDNA
maternal transmition only but can effect male
x linked inheritance
males are hemizygous so no male to male transmision
all daugters of affected male are heterozygous
female give 50/50 affected to sons and 50/50 carrier daughters
obligate carrier
heterozygous who have affected offspring
EcoR1 and XLA gene mapping
creates two short segments
short means mutated long if not
both if carrier
X linked only one for male, 2 for female
LOD scores
> 3 linkage of mednelian trati
>2 for multigene trait
c
% recombination
recombinates/(progeny+R)
highest Z
log(c)
best hypothesis
brutons diseas
x linked agammaglobulinemia
BTK mutant arrests B cell development
