Receptor tyrosine kinases often are: A.phosphorylate serine residues to activate down stream signal transduction B.shutt

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Receptor tyrosine kinases often are:
A.phosphorylate serine residues to activate down stream
signal transduction
B.shuttled to the nucleus to activate
transcription
C.dimerize and autophosphorylate to begin signal
transduction
D.are inactivated by ligand binding
The EphA4 receptor signals for growth cone collapse by
the following signal transduction pathway.
Activation of Rho to relay signals to the
cytoskeleton.
Activation of Rap to activate integrin
signaling.
Activation of Ran to regulate mitotic spindle
assembly.
Activation of Rheb to stimulate mTOR.
Sar1 GTPase plays an important role in COPII coat
formation. Scientists generated a Sar1 GTPase mutant, in which the
GTPase activity is lost. How this mutant would affect the
COPII-mediated transport?
No effect would be observed.
COPII-coated vesicles can’t form at all.
COPII-coated vesicles can form, but the coat can’t be
disassembled and thus the vesicles can’t fuse with the target
membrane.
COPII-coated vesicles can form normally, but the coat
can’t be disassembled. However, the coated vesicles can still dock
and fused with the target membrane.
Please answer all questions no need for explanation ASAP.