The adaptor role of SHP-1 in SHP-1–mediated negative regulation of cytokine-receptor signaling. The adaptor role of SHP-1 is critical in SHP-1–mediated negative regulation of cytokine-receptor signaling. The steps in this regulation are as follows: (1) SHP-1 protein tyrosine phosphatase is recruited to receptor/Jak2 complex upon receptor ligand binding. (2) This process results in SHP-1 tyrosine phosphorylation on its C-terminal tyrosine residues, leading to the recruitment of Grb2 and its associated protein SOCS-1. (3) SOCS-1 is targeted to Jak2, leading to (4) down-regulation of Stat5 activation.