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Signal Transduction
Metazoans
JAK-STAT Pathway
Cytokine-driven signaling from receptor to gene expression via STAT dimerization.
Overview
The JAK-STAT pathway provides a direct mechanism for translating extracellular signals into transcriptional responses. Cytokine binding induces receptor dimerization and activation of associated JAK kinases. JAKs phosphorylate STATs, which dimerize and translocate to the nucleus to drive transcription of target genes. Negative regulators include SOCS proteins, PIAS, and protein tyrosine phosphatases.
Cellular Location
Cytoplasm → Nucleus
Clinical Significance
Critical for immune regulation and hematopoiesis; JAK2 V617F mutation drives myeloproliferative neoplasms; target of JAK inhibitors (ruxolitinib, tofacitinib).