The SH2 domain containing inositol 5-phosphatase SHIP2 displays phosphatidylinositol 3,4,5-trisphosphate and inositol 1,3,4,5-tetrakisphosphate 5-phosphatase activity

Distinct forms of inositol and phosphatidylinositol polyphosphate 5-phosphatases selectively remove the phosphate from the 5-position of the inositol ring from both soluble and lipid substrates, SHIP1 is the 145-kDa SH2 domain-containing inositol 5-phosphatase expressed in haematopoietic cells, SHIP2 is a related but distinct gene product. We report here that SHIP2 can be expressed in an active form both in Escherichia coli and in COS-7 cells, A truncated 103-kDa recombinant protein could be purified from bacteria that display both inositol 1,3,4,5-tetrakisphosphate (InsP(4)) and phosphatidylinositol 3,4,5-trisphosphate (PtdIns(3,4,5)P-3) phosphatase activities. COS-7 cell lysates transfected with SHIP2 had increased PtdIns(3,4,5)P-3 phosphatase activity as compared to the vector alone. (C) 1998 Federation of European Biochemical Societies.