Human cDNA clones encoding two different isoforms of the nerve terminal protein SNAP-25

Two distinct cDNA sequences, corresponding to alternative isoforms of the human nerve terminal protein SNAP-25 (synaptosomal associated protein of 25 kDa), were cloned and characterized. Sequence analysis demonstrated that the two isoforms are generated by alternative splicing between two distinct but homologous exons 5, a and b each encoding 39 amino acids (aa). Although the two isoforms, SNAP-25a and SNAP-25b, differ by only 9 aa, this domain encodes the portion of the protein that is a substrate for post-translational fatty acylation, and therefore might be important for regulating subcellular localization and membrane targeting.