Tyrosine kinase substrate that inhibits growth-factor-mediated activation of MAP kinase (PubMed:11493923). Negatively regulates hematopoiesis of bone marrow (PubMed:15465815). Inhibits fibroblast growth factor (FGF)-induced retinal lens fiber differentiation, probably by inhibiting FGF-mediated phosphorylation of ERK1/2 (PubMed:29501879). Attenuates actin stress fiber formation via inhibition of TESK1-mediated phosphorylation of cofilin (By similarity). Inhibits TGFB-induced epithelial-to-mesenchymal transition in lens epithelial cells (PubMed:25576668). Homodimer and heterodimer (By similarity). Able to interact with SPRED2 to form heterodimers (By similarity). Interacts (via C-terminus) with TAOK1/MARKK (via C-terminus); the interaction does not affect TAOK1 kinase activity (By similarity). Interacts (via C-terminus) with TESK1 (via C-terminus); the interaction inhibits TESK1 kinase activity (PubMed:17974561). Interacts with CAV1 (By similarity). Interacts with RAS (PubMed:11493923). Interacts with palmitoyltransferase ZDHHC17/HIP14; the interaction leads to palmitoylation of SPRED1 (PubMed:24705354). Localized in cholesterol-rich membrane raft/caveola fractions. Expressed in brain. Weakly expressed in lung, heart, liver, kidney, intestine, spleen, testis, thymus, colon and ovary. Also expressed in embryonic tissues such as heart, lung, liver and brain. Highly expressed in IL3-dependent hematopoietic cell lines (Ba/F3 and MC/9) and bone marrow-derived mast cells (BMMC). Palmitoylated by ZDHHC17/HIP14. Ubiquitinated. Phosphorylated on tyrosine.