cell cycle control Flashcards
phases of the cell cycle
interphase, prophase, prometaphase, metaphase, anaphase, telophase, cytokinesis
how is proliferation controlled
phosphorylation, dephosphorylation, production or degradation of proteins
what is a cyclin
present throughout the whole cell cycle at varying concentrations, inactive
what are cyclin dependent kinases
must be bound to cyclins in order to phosphorylate proteins
what are cyclin kinase inhibitors
they are proteins that bind to CKDs and inhibit them from phosphorylating other proteins
proteins involved at S-phase DNA replication checkpoint
S-CDK (cyclin A and CDK2)
how do the proteins work at S-phase DNA replication checkpoint
recruits DNA polymerase to trigger DNA replication, degrades CDC6 to stop re-replication
proteins involved at M phase chromosome segregation checkpoint
M-CDK (cyclin B and DK1) and APC - anaphase promoting complex
how do the proteins work at M phase chromosome segregation checkpoint
M-CDK phosphorylated by CDC6 causing chromosomal condensation, cytoskeleton rearrangements, laminin phosphorylation
role of APC
catalyses degradation of securin so chromatids can separate by separase, activates M-CDK to break down cyclins and cause decondensation
proteins involved in G1 to S continued proliferation checkpoint
G1-CDK (cyclin D and CKD4/6)
how do proteins in G1 to S continued proliferation checkpoint work
Rb phosphorylation and inactivation, E2F released and gene activation for S phase proteins
what proteins are involved in G1 to S DNA damage checkpoint
p53
how does G1 to S DNA damage checkpoint work
when damage is present, p53 has low affinity for mdm2 (not broken down), it accumulates causing transcription of CKI (P21), repair proteins and cell death regulators. if DNA cannot be fixed cell will die
