Ras Proteins Flashcards
what are the three types of ras?
K H N
what is ras?
a small gtp-ase
molecular switch
what does ras do?
regulates diverse cell signalling cascades: proliferation, differention, apoptosis etc via tyrosine kinases
what is the classic ras pathway?
grb2 binds to trk using sh2 domain
grb2 recruits sos1 (gef enzyme)
ras gap changes ras gdp for ras gtp
what is a classic effector pathway of ras?
P13K which is for surival, metabolism etc
what are three proteins in the P13K pathway?
IRS
BAD
AKT
what are two proteins in the MAPK pathway?
GRB2
SOS
what is MAPK pathway for?
proliferation
differentiation
what regions do all ras isoforms contain?
CAAX box
target domain
linker domain
how many and what are the cystein residues in n and h ras?
n ras has 1 residue called c181
h ras has 2 residues called c181 and c184
what is palmitylation
addition of a fatty acid
what is the purpose of cystein residue c181?
moving from golgi body to plasma membrane
what are lipid domains?
regions of membrane where receptors, signalling molecules etc are borught in close proximity
favourable kinetics so efficent traffickinh etc
what are four effector proteins of ras?
GAPs
P13K
RAF
MAPK
how is MAPK linked to cancer?
GRB2 is bound to tyrosine kinase receptors and sos binds to GRB2 which activates ras
but if ras mutated then pathway goes ras->raf->mek->erk->mutations in transcribed dna
uncontrolled growth and division etc
