SHIPs ahoy

In 1996 three groups independently cloned a hemopoietic specific, are homology 2-containing inositol 5'-phosphatase which, based on its structure, was called SHIP. More recently, a second more widely expressed SHIP-like protein has been cloned and called SHIP2. Both specifically hydrolyze phosphatidylinositol-3,4,5-trisphosphate and inositol 1,3,4,5-tetrakisphosphate in vitro. Moreover, SHIP has been shown in vivo to be the primary enzyme responsible for breaking down phosphatidylinositol-3,4,5-trisphosphate to phosphatidylinositol-3,4-bisphosphate in normal mast cells and, as a result, limits normal and prevents inappropriate mast cell degranulation. Because of their ability to break down phosphatidyrinositol-3,4,5-trisphosphate the SHIPs have the potential to regulate many, if not all, phosphatidylinositol-3-kinase induced events including, proliferation, differentiation, apoptosis, end cell activation, cell movement and adhesion and will thus likely be the subject of intensive research over the next few years. (C) 1999 Elsevier Science Ltd. All rights reserved.