SDS-PAGE (A) and Western blotting (B) analyses of Glaucosoma buergeri muscles. Band 1, blue arrow: a protein homologous to the smooth-muscle specific protein transgelin, identified using LC-MS/MS followed by a database search, was revealed only in the smooth muscle. Band 2 red arrow: indicates myosin light chain 3 (see Additional File 2) from striated muscle (trunk white and anterior sonic muscle). B. Troponin T (upper panel) present in striated but not in the internal smooth muscle and alpha sacromeric actin (lower panel) present in muscles but not in the tendon. Actin, as expected, is expressed at a lower level in smooth than in striated muscles.