Choose only one correct answer QUESTION 1 Transautophosphorylation occurs in whi
ID: 56593 • Letter: C
Question
Choose only one correct answer
QUESTION 1
Transautophosphorylation occurs in which two of the following signaling pathways?
a.GPCR and RTK pathways
b.RTK and Integrin/FAK pathways
c.S/TKR and PKA pathways
d.GPCR and Ras pathways
e.MAPK and cAMP pathways
QUESTION 2
Which of the following receptors are activated by GTP?
a.G protein coupled receptors only
b.tyrosine kinase receptors only
c.both G protein coupled receptors and tyrosine kinase receptors
d.neither G protein coupled receptors nor tyrosine kinase receptors
QUESTION 3
Why can both GPCR and RTK pathways activate calmodulin?
a.Because both activate PLC
b.Because both activate PI3K
c.Because both trigger an action potential
d.Because both activate Ras
e.Because both activate PKA
QUESTION 4
Ion channel receptors __________ enzymes. They __________ bind signaling ligands.
a.are, do
b.are not, do
c.are, do not
d.are not, do not
QUESTION 5
PIP2 is cleaved by ___________ to produce _____________.
a.phosphodiesterase, DAG and IP3
b. phospholipase C, DAG and IP3
c. phosphodiesterase, DAG and calcium
d. phospholipase C, DAG and calcium
QUESTION 6
Why are integrins considered to be signaling proteins?
a.Because they bind ECM
b.Because they bind heterotrimeric G proteins
c.Because they bind FAK
d.Because they bind MAPK
e.Because they bind Sos
QUESTION 7
Why isn’t tubulin considered a G protein?
a.Because it doesn’t propagate a signal in a signaling pathway
b.Because it doesn’t bind to GPCR
c.Because it doesn’t bind to a GEF or a GAP
d.Because it doesn’t undergo transautophosphorylation
e.Because it doesn’t bind GTP
Explanation / Answer
1) Transautophosphorylation occurs in two signaling pathways such as GPCR and RTK pathways. The G - protein coupled receptors and receptor tyrosine kinases undergo trans phosphorylation during translational processing to get activated and to activate other kinases. Opton a is correct.
2) Both G protein coupled receptors and tyrosine kinase receptors are activated by GTP. But, GPCRs are mainly to get activated by GTP than tyrosine kinase receptors (RTKs). The RTKs are known to activated by Ras protein which inturn activated by GTP. Hence, option c is correct.
3) Both GPCR and RTK pathways activate calmodulin because both activate phospholipase C to release the calcium ions through a signal cascade. Option a is correct.
4) Ion channel receptors are not enzymes. They donot bind signaling ligands.
Ion channel linked receptors or ion channels are for passage of anions and cations, and are a large family of multipass transmembrane proteins. These are activated by rapid signaling events generated by neurons. They are also known as ligand-gated ion channels. Opening and closing of ion channels is controlled by neurotransmitters. Option d is correct.
5) PIP2 is cleaved by phospholipase C to produce DAG and IP3. Option b is correct.
6) integrins considered to be signaling proteins because they bind heterotrimeric G proteins like EGF. Option b is correct.
7) Tubulin is not considered a G protein because it doesn’t propagate a signal in a signaling pathway. Option a is correct.