Expression, Purification, Crystallisation and X-ray Crystallographic Analysis of a Truncated Form of Human Src Homology 2 Containing Inositol 5-Phosphatase 2

The Src homology 2 containing inositol 5-phosphatase 2 (SHIP2) catalyses the dephosphorylation of the phospholipid phosphatidylinositol 3,4,5-triphosphate (PI(3,4,5)P-3) to form PI(3,4)P-2. PI(3,4,5)P-3 is a key lipid second messenger, which can recruit signalling proteins to the plasma membrane and subsequently initiate numerous downstream signalling pathways responsible for the regulation of a plethora of cellular events such as proliferation, growth, apoptosis and cytoskeletal rearrangements. SHIP2 has been heavily implicated with several serious diseases such as cancer and type 2 diabetes but its regulation remains poorly understood. In order to gain insight into the mechanisms of SHIP2 regulation, a fragment of human SHIP2 containing the phosphatase domain and a region proposed to resemble a C2 domain was crystallized. Currently, no structural information is available on the putative C2-related domain or its relative position with respect to the phosphatase domain. Initial crystals were polycrystalline, but were optimized to obtain diffraction data to a resolution of 2.1 . Diffraction data analysis revealed a P2(1)2(1)2(1) space group with unit cell parameters a = 136.04 , b = 175.84 , c = 176.89 . The Matthews coefficient is 2.54 (3) Da(-1) corresponding to 8 molecules in the asymmetric unit with a solvent content of 51.7 %.