Lecture 3 - Self-sufficiency in growth signals

Question 1

Hillocks

Answer 1

Related pathways

Question 2

unseen small hills

Answer 2

passenger mutations

Question 3

comparison of two colorectal cancers

Answer 3

by large don’t show many common mutations, but do show they’re in the same pathways

Question 4

Probability of getting cancer is…

Answer 4

proportional to the number of changes

this increases with age

Question 5

Statistics show there are over….. mutations in any given cancer

Answer 5

over 15

Question 6

Protein phosphorylation

Answer 6

dynamic and reversible process which changes the functionality of protein targets

Question 7

Growth factor signalling pathway

Answer 7

growth factor binds to RTK, causes dimerisation and cross-phosphorylation
causes Grv2 to bind
Ras-Gef binds to Grb2 adaptor protein
causes GDP to GTP hydrolysis which activates Ras
causes downstream signalling

Question 8

Residues 12 and 61 are….

Answer 8

gatekeepers for GTP binding

Question 9

Guanine structure is different..

Answer 9

depending if GTP or GDP are bound, determines active vs. inactive

Question 10

Three ways self-sufficiency might arise

Answer 10

Growth factor presence
Ligand-indpendent signalling
GTPase switch off failure

Question 11

Growth factors and self-sufficiency

Answer 11

normally GF produced by another cell, but cancer cells can produce their own GF so no longer require environmental signalling

Question 12

Ligand-indpendent signalling and self-sufficiency

Answer 12

i.e. no extracellular signalling

RTKs turn each other on without ligand binding

Question 13

GTPase switch off failure in self-sufficiency

Answer 13

usually 2 forms - GTP or GDP bound

Ras always on with constitutive downstream signalling