C18 Cell cycle control Flashcards
cell cycle checkpoint control is a feedback regulated (positive/negative) control
negative
Cell cycle is controlled by ? activated protein kinases
cyclically
Entry into M phase is initiated as ? is activated by appearance of ?
M-cdk ,M- cyclin
cdk,cyclin phosphorylation is controlled by these three enzymes
inhibitory kinase, activating kinase, activating phosphatase
Activated M-cdk participates in ? which activates other M-cdk
positive feedback loop
M-cdk acts to phosphorylate key proteins to drive cell to ?
mitosis
S-cdk triggers ?
DNA replication
How are cdks turned off
degradation by proteasomes by being marked with ubiquitine
Protein that starts signalling of DNA damage by activating protein kinase chk2
ATM
Common growth signal
EGF
braking mechanism that keeps cell s from proliferating
Rb protein
? inhibits growth of myoblasts that form muscle cells
myostatin
apoptosis is mediated by intracellular ?
proteolytic cascade
apoptosis summary
procapsases activated by proteolytic cleavage to active capsases which activate additional procapsases and ultimately degrade many key proteins
Apoptosis is regulated by ? proteins
Bcl-2
Inducers of apoptosis
tissue necrosis factor receptor, DNA damage, stress
Intrinsic apoptosis
internal cellular damage triggers release of cytochrome c from mitochondria. cyt c activates procaspase-9
? or ? influence permeability of mitochondria, releasing cyt c
bad or bax
Cancer cells affected genes fall into two classes:
oncogenes and loss of function of tumor supressor genes
oncogenes
mutant genes in proliferative genes that result in overexpression of the protein. Normal version called proto-oncogenes. Only one copy of gene must be mutated to become active.
? stimulate cell division
mitogens
? promote cell survival by suppressing apoptosis
survival factors
