Pathways regulating survival, growth and proliferation

Question 1

Why can a cells defeat role be considered to die?

Answer 1

If it doesn’t recieve signals it becomes apoptopic and dies

Question 2

How does the RAS/MAP kinase (ERK) pathway relate to the cell cycle?

Answer 2

MAPK pathways relay, amplify and integrate signals from a diverse range of stimuli

and elicit an appropriate physiological response including cellular proliferation, differentiation, development, inflammatory responses and apoptosis

in mammalian cells.

Question 3

What do checkpoints in G1 of the cell cycle do?

Answer 3

detect if they need to grow and divide

detect if environment is favourable

Question 4

What is the Protein-tyrosine kinase receptor–

Ras – MAP kinase cascade?

Answer 4

Growth factor activated signalling pathway used by many PTK receptors that results in changes of gene expression and cell cycle.

Pathway activated in many cancers!

Question 5

What enzyme family mediates the addition of a phosphate group?

Answer 5

Kinase

Question 6

What enzyme family catalyses the removal of a phosphate group?

Answer 6

phosphotase

Question 7

What are the two main classes of protein kinases?

Answer 7

Protein Serine/Threonine kinases

Protein Tyrosine kinases

Question 8

What is the approximate size of the SH2 and SH3 protein domains?

Answer 8

100 amino acids long

Question 9

What is an SH2 domain?

Answer 9

Independently folding protein modules.

~ 100 amino acids in length

Found in a wide range of signalling molecules.

Regulate activation of signalling proteins via protein-tyrosine kinases.

SH2 domains bind to phosphorylated tyrosine residues when presented within a specific sequence context.

e.g., for PI 3-kinase - Y(P)xxM

for Grb2		- Y(P)xNx

Mediate the formation of signalling complexes between activated protein-tyrosine kinase receptors and the downstream generators of 2nd messenger molecules.