Which of the following most specifically explains why relay proteins only bind receptor tyrosine kinases (RTK) after activation? a. SH2 domains are only present in the relay proteins after activation
b. SH2 domains in the relay proteins only bind Tyr that has been phosphorylated in the RTK
c. SH2 domains in the relay proteins must be phosphorylated on Tyr to bind RTK
d. SH2 domains in the relay proteins only phosphorylate Tyr in the RTK after activation
e. SH2 domains in the RTK must be phosphorylated on Tyr to bind relay proteins