The highly conserved synapse protein SNAP-25 displays sequence variabilityin the cockroach Leucophaea maderae

SNAP-25 (synaptosome-associated protein of 25 kD) is attached to the intrac ellular side of presynaptic membranes where it serves as a target receptor for the vesicle docking machinery prior to release of neurotransmitter. SNA P-25 displays a high degree of sequence conservation between vertebrates an d Drosophila melanogaster. To obtain more information about conserved regio ns of SNAP-25, we have isolated cDNA clones from the cockroach Leucophaea m aderae. One clone (Lm1) encoded a full-length SNAP-25 protein and its deduc ed amino acid sequence is 77% identical to Drosophila SNAP-25. Surprisingly , the cockroach protein is 17 amino acids shorter than Drosophila SNAP-25 a t the carboxy terminus. Four other cDNA clones encode parts of SNAP-25 and each clone has distinct characteristics, including amino acid replacements and unique carboxy termini. Thus, the highly conserved protein SNAP-25 disp lays unexpected sequence variability in the cockroach that may indicate spe cialized SNAP-25 isoforms. (C) 1999 Elsevier Science Inc. All rights reserv ed.