Lecture 15 - Apoptosis and senescence

Question 1

name the kinase on histone octamers which senses damaged DNA?

Answer 1

sensor PIKK kinase

Question 2

after sensor PIKK kinase on damaged histone octamers senses damage, which histone terminus is phosphorylated?

Answer 2

H2AX c terminus

Question 3

name the mediators in histone octamers sensing DNA damage

Answer 3

53BP1, MDC1, BRCA1

Question 4

give examples of downstream targets following histone octamers sensing DNA damage, which lead to p53 arresting the cell cycle/apoptosis

Answer 4

CHK1, CHK2, MRE11, RAD50, NBS1

Question 5

after stabilisation, what does the tumour suppressor p53 form? what do they bind to acting as transcription factors?

Answer 5

tetramers, DNA

Question 6

does continuous activation of p53 accelerate ageing?

Answer 6

yes

Question 7

define cell senescence in terms of proliferation

Answer 7

a permanent and irreversible arrest of cell proliferation

Question 8

give 2 examples of what cell senescence can result from

Answer 8

uncapped telomeres or insufficient DNA repair by DDR

Question 9

name two methods of mediated apoptosis (2 molecules) which act as cooperating checkpoints, having similar potential to contribute to ageing

Answer 9

p21 mediated and PUMA mediated