 This phosphorylation activates STAT5 which then makes its way to the nucleus to induce expression of target genes including suppressor of cytokine signaling 3 (SOCS3), a strong inhibitor of insulin signaling.Research has demonstrated that overexpression of CRBP-I increases the ability of RBP-ROH complex to phosphorylate STRA6 and, later, JAK2 and STAT5.Suppressing CRBP-I, on the other hand, led to decreased ability of RBP-ROH complex to phosphorylate STRA6 and signaling components.