08c: Cell Signaling Flashcards
Receptor tyrosine kinases have which structure? And which domains?
Single-pass transmembrane receptors; ligand-binding domain outside cell and kinase domain inside cell
Receptor tyrosine kinases bind (X). What is their primary function?
X = growth factors
Control rate of cell growth and proliferation
T/F: all RTK ligand so control cell proliferation.
False - insulin receptor does not
First step in in RTK signaling (once ligand(s) bind):
Dimerization of the receptors
RTK ligands are (monomers/dimers/other).
Can be either monomers or dimers
After ligand binds and RTK receptors (dimerize/separate), which event takes place?
Dimerize;
Phosphorylation of one receptor by another (and sometimes vice versa)
RTK are phosphorylated on which residue(s) and domain(s)?
Tyrosine residues on their kinase (intracellular) domains
List the key protein (X) that recognize phosphorylated RTK.
X = domains
- SH2
- PTB
- SH3
- PH
SH2 domains specifically recognize:
Phosphorylated tyrosine, followed by X, X, Hy
PTB domains specifically recognize:
N, X, P, Y(phosphorylated)
SH3 domains specifically recognize:
Proline-rich sequences
PH domains specifically recognize:
Phosphorylated lipids
T/F: One RTK can interact with several domains, activating several pathways, at once.
True
Overall result of stimulation of MAP kinase pathway.
Increased cell proliferation
In MAPK pathway, (X) binds activated (Y) receptors via which domain(s)?
X = GRB2 Y = RTK
Via its SH2 domain
Bound and activated GRB2 uses its (X) domain(s) to:
X = two SH3 domains
To recruit and bind SOS to plasma membrane
GRB2 is referred to as a(n) (X) protein.
X = adaptor
SOS has which specific function?
GEF (GTP/GDP Exchange factor) for Ras
Which form of Ras is active?
GTP-bound Ras
What is the only real function of Ras? Are there enzymes that assist in its function?
GTPase (a small, slow one)
Yes - GAP
(X) recruits Ras to the cell membrane.
Ras is already tethered to cell membrane. No protein recruits it.
(X) is tethered to the cell membrane via 1 or 2 anchors, composed of (Y).
X = Ras Y = farnesyl and (sometimes) a second FA anchor
Activates Ras has which subsequent, immediate effect?
Binds Raf and recruits it to cell membrane
T/F: Ras and Raf must be bound to cell membrane to be active.
True