Question

Which of the following signaling components directly amplify the signal? (can select more than one)

a. protein kinases

b. receptor tyrosine kinases

c. first messengers

d. second messengers

e. signaling domains

Answer 1

d. Second messengers:

An significant characteristic of the second messenger signaling scheme is that it is possible to couple second messengers downstream to multi-cyclic kinase cascades to significantly amplify the power of the initial first messenger. Example: RasGTP signals, connected to the MAPK cascade to amplify the allosteric activation of transcription elements like Myc and CREB.

b. Receptor Tyrosine Kinases:

RTK are basically receptors and they can also act as signal amplifiers. Example: As with GPCRs, GTP-binding proteins play an important part in signal transduction from the activated RTK into the cell. GPCR assigns proteins to particular subdomains of membranes where they engage in signaling when activated. Small G proteins that activate guanine nucleotide exchange factors like SOS1 are activated by activated RTKs in turn. These exchange variables can activate smaller G proteins once activated, thereby amplifying the original signal of the receptor.