Identification of three new splice variants of the SNARE protein SNAP-23

SNAP-23 has an important role in protein-trafficking processes in mammalian cells and until yet two isoforms of SNAP-23 (SNAP-23a and SNAP-23b) have been described. In the present report, we have identified the existence of three new SNAP-23 isoforms (named SNAP-23c, SNAP-23d, and SNAP-23e), which arise from alternative splicing. By RT-PCR all five splice variants were shown to be expressed in four different human inflammatory cells (eosinophils, basophils, neutrophils, and peripheral blood mononuclear cells). Transfection of the human basophilic KU-812 cell line with plasmid constructs containing the cDNAs of the five splice variants located SNAP-23a and SNAP-23b primarily in the plasma membrane. The other three splice variants were localized both intracellularly and in the plasma membrane.