Stomatin-related olfactory protein, SRO, specifically expressed in the murine olfactory sensory neurons

We identified a stomatin-related olfactory protein (SRO) that is specifically expressed in olfactory sensory neurons (OSNs). The mousesrogene encodes a polypeptide of 287 amino acids with a calculated molecular weight of 32 kDa. SRO shares 82% sequence similarity with the murine stomatin, 78% withCaenorhabditis elegansMEC-2, and 77% withC. elegansUNC-1. Unlike other stomatin-family genes, thesrotranscript was present only in OSNs of the main olfactory epithelium. Nosroexpression was seen in vomeronasal neurons. SRO was abundant in most apical dendrites of OSNs, including olfactory cilia. Immunoprecipitation revealed that SRO associates with adenylyl cyclase type III and caveolin-1 in the low-density membrane fraction of olfactory cilia. Furthermore, anti-SRO antibodies stimulated cAMP production in fractionated cilia membrane. SRO may play a crucial role in modulating odorant signals in the lipid rafts of olfactory cilia.