Sarcolemma Associated Protein (SLMAP)

Sarcolemmal membrane-associated protein is a protein encoded by the SLMAP gene. Three alternately spliced isoforms, termed SLAP1, SLAP2, and SLAP3, differing at their 5-prime ends, were identified. The 3 cDNAs predicted proteins of 322, 402, and 639 amino acids, with predicted masses of 37, 46, and 74 kD, respectively. Each of the predicted proteins contained a putative transmembrane domain at its carboxy-terminal tail and 2 potential leucine zipper motifs. SLAP showed extended low-level homology with myosins and other coiled-coil proteins. Northern blot analysis of rabbit tissues revealed 3 mRNAs of 5.9, 4.5, and 3.5 kb, each with a distinct pattern of expression. Immunostaining of rat heart tissue sections demonstrated that SLAP had a reticular pattern of expression in the sarcolemma.