FMS Week 1 Flashcards
Ataxia telangiectasia
Results from mutations in ATM gene, spider veins, loss of motor control, immunodeficiency, sensitivity to radiation
Neurofibromatosis
Inherited cancer syndrome caused by mutation in NF1 gene
DNA polymerase δ
Leading and lagging strand synthesis and base excision repair
XPC
NER gene, xeroderma pigmentosum assoc.
GEF
A GTP meditator for G-proteins
What is the second step of RNA modification?
The RNA is cleaved at the polyA signal, the tail is synthesized by polyA polymerase, PABPN1 (poly A binding protein 1) stops synthesis at 200-300bp
what are the similarities of the 2 apoptosis pathways?
they both activate the same effector caspases
mutation in mismatch repair gene (MMR)
Lynch syndrome, most commonly results in hereditary non-polyposis colon cancer (HNPCC)
2 types of anchoring junctions
adherens junctions and desmosomes
aflatoxins
carcinogens from peanut/grain mold
what is the biggest difference between dephosphorylation and GTP hydrolysis?
GTP hydrolysis is not mediated by an enzyme
Bloom syndrome
results from mutation in BLM gene of homologous recombination, short stature, narrow face with prominent nose, skin-sun sensitivity, facial rash, immunodeficiency, cancer, possible mental retardation
translation initiation
40s subunit joins mRNA at 5’ region, scans for the first start codon in the proper context, 60s subunit joins and translation begins
carcinogens from charred meat
heterocyclic amines
aneuploidy
less or more than an exact multiple of the haploid set of chromosomes
erythromycin
binds to the 50s subunit and inhibits translocation (prokaryotes)
what type of molecules are second messengers?
small molecules that aplify the signal of the first messenger (ligand)
1000-fold increase of skin cancers, “children of the night”
Xeroderma pigmentosum
where does DNA methylation occur?
C-G adjacent basepairs
JAK-STAT Pathway
cytokines bind receptor, JAKs phosphorylate each other, JAK binds and activates STAT through phosphorylation, STAT (complex) is a transcription factor
cycloheximide
inhibits translocation (blocks translational elongation)(eukaryotes)
What is PTEN?
PTEN inhibits PIP2 to PIP3 secondary messaging, indirectly leading to promotion of apoptosis (AKT indirectly leads to degradation of p53) and inhibition of cell growth
Werner Syndrome
results from mutations in WRN gene of homologous recombination and DNA replication, short stature, premature aging, cancer
CNV
copy number variants
CDKN2 family
bind and inhibit only D-CDK4/6 (restriction point)
What effect do Xrays have on DNA?
strand breakage
tight junction
seals gaps between epithelial cells
what is myc?
a transcription factor for cyclin D
receptor of RAS-MAPK
tyrosine kinase
ATM gene
gene associated with homologous recombination in double-stranded breakage
how do hydrophillic signals act?
surface receptors trigger signal transduction through to effector proteins that can act both inside and outside the nucleus
what facilitates phosphorylation?
ATP (to ADP) and a protein kinase
XPA
NER gene, xeroderma pigmentosum assoc.
DNA mismatch repair
Guided by mismatch proofreading proteins cut out segment of strand with “nick” so that DNA pol can resynthesize
prophase
chromosomes condense, mitotic spindle forms, nucleus disassembles, chromosomes begin attaching to mitotic spindle
metaphase
chromosomes line up
cytokine
small proteins that stimulate differentiation/proliferation of immune cells
Bad
apoptotic sensor
FANC
interstrand DNA crosslink repair gene, assoc. w/ fanconi anemia
pemphigus vulgaris
blistering disease caused by autoantibodies to desmosomal proteins
DNA polymerase ε
Leading strand synthesis and base excision repair
7-TM receptor
large serpentine domain that is usually coupled to large G-protein
membrane-mediated signalling
signals communicate through the membranes of adjacent cells
what family is p16?
CDKN2
2 ways splicing can regulate translation
alternative introns/exons, differential splice sites within an intron
cyclin-CDK G2/M transition (entry to mitosis)
A-CDK1
what is the biggest difference between dephosphorylation and GTP hydrolysis?
GTP hydrolysis is not mediated by an enzyme
carcinogens from peanut/grain mold
aflatoxins
Ras
small G-protein, activated (GTP) through tyrosine-kinase complexes
what are the 2 pathways of apoptosis?
Intrinsic (mitochondrial) and extrinsic (death receptor)
what is a procaspase?
an inactive caspases that cleave eachother to activate, then cleave executioner caspases to activate them in a cascade
snRNPs
guide splicing process, make up the splicosome
Xeroderma Pigmentosum
high risk of all skin cancers, results from mutation in any XP gene (NER gene): XPA, XPC, ERCC2, ERCC4, ERCC5
actin-linked cell matrix junction
actin anchors to extracellular matrix (basal lamina). basal “adherens”
What are the pro-apoptotic sensors and what do they do?
Bad, Bim, Bid, Puma, and Noxa. They are BH-3 only proteins. They sense cellular stress/damage and take out the anti-apoptotic regulators to start apoptosis.
receptor of PI3K-AKT pathway?
receptor dimers with intrinsic kinase domains or that bind intracellular kinases
direct ligation
DNA-protein kinase and Ku allign dsDNA breaks, usually results in bp deletions
Restriction point pathway
Growth factors trigger signalling pathway that upregulates myc (cyclin D transcription factor), cycD activates CDK4/6, D-CDK4/6 phosphorylates Rb, inactivated Rb (hyperphosphorylated) no longer inactivates E2F, freed and activated E2F is transcription factor for S phase genes such as cyclin A
WRN
gene involved in homologous recombination and DNA replication, codes for a DNA helicase
Bcl-XL
anti-apoptotic regulator
BRCA1/2
gene associated with homologous recombination in double-stranded breakage
non-homologous end joining
resects ends to uncover 2-3 nucleotide micro-homology
fragile-X syndrome
caused by nucleotide expansion mutations
RAS-MAPK pathway
growth factors bind receptor, Ras is activated by GTP exchange factor (GEF), Ras activates (p) Raf, Raf activates (p) Mek, Mek activates (p) Erk (MAPK). Erk phosphorylates target proteins including transcription factors such as Myc
membrane-mediated signalling
signals communicate through the membranes of adjacent cells
ERCC2
NER gene, xeroderma pigmentosum assoc.
GPCRs
large G-proteins
how to hydrophobic signals act?
the enter the plasma membrane and bind with receptors in the cytoplasm, then move into the nucleus
myotonic dystrophy
caused by nucleotide expansion mutations
euchromatin
more relaxed chromatin, more transcriptionally active
what is p53?
a tumor supressor gene that is involved in the restriction point pathway, DNA damage checkpoint pathway, and the apoptosis pathway
cAMP-PKA pathway
Peptide hormone is ligand for 7TM receptor, which activates adenylate cyclase, which activates (p) cAMP, which removes inhibitor on protein kinase A (PKA), PKA enters the nucleus and activates transcription factors
receptor of JAK-STAT
cytokine receptor coupled to JAK
steroid receptors
gene-specific transcription factors that are activated by hormone binding
how does methylation deactivate genes?
attracts histone deacytylases (HDAC), compacts histones around promoters
mitotic/spindle assembly checkpoint
Mad2 recruited to kinetochore, Mad2 inhibits APC/C (an ubiquitin ligase), mitotic proteins and cyclins (A&B) cannot be degraded by 26S, and the cell cycle is arrested in mitosis until securin can restore loose chromatids
steroid receptors
gene-specific transcription factors that are activated by hormone binding
cytokine
small proteins that stimulate differentiation/proliferation of immune cells
HNPCC
“Lynch syndrome”, colorectal cancer, MMR mutation: MSH2/3/6, MLH1, PMS1/2