Growth hormone binds to its receptor on hepatocytes and activates the JAK-STAT signaling pathway. Which specific STAT protein is predominantly phosphorylated and activated by JAK2 in growth hormone signaling?
- A STAT1
- B STAT3
- C STAT5 ✓
- D STAT6
Correct answer: C. STAT5
Explanation
Growth hormone receptor signals through JAK2, which predominantly phosphorylates STAT5b. STAT5 is the key transcription factor mediating GH effects on IGF-1 production and longitudinal growth. STAT1 is activated by interferons, STAT3 by IL-6 family cytokines, and STAT6 by IL-4 and IL-13. This specificity is determined by the receptor-JAK-STAT pairing.
Reference: Ganong's Review of Medical Physiology, 26th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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