IDENTIFICATION AND CHARACTERIZATION OF A NOVEL SPLICE VARIANT OF SYNAPTOJANIN1

Synaptojaninl, the major constitutively active PtdInsP(3) 5-phosphatas e activity in rat brain, is one of two closely related proteins both e xtensively spliced in their C-terminal proline rich domain. We describ e here the discovery of a novel splice variant of synaptojaninl which misses the major N-terminal part of the SAC1 domain. This Delta SAC-sy naptojaninl is expressed in rat brain tissue as shown by Northern and Western analysis, However, the deletion of the SAC1 domain does not al ter PtdInsP(3) 5-phosphatase activity demonstrating that the SAC1 doma in is not necessary for catalytic function. (C) 1998 Federation of Eur opean Biochemical Societies.