Polypeptide gp95. A unique glycoprotein of olfactory cilia with transmembrane receptor properties

Polypeptide gp95 is a major glycoprotein present in preparations of isolated ciliary extensions from frog olfactory sensory neurons (Chen, Z., and Lancet, D. (1984) Proc. Natl. Acad. Sci. U.S.A. 81, 1859-1863). We report here that gp95 is distinct among the ciliary polypeptides in having several properties that make it a plausible receptor candidate: it is specific to olfactory cilia, it has the appropriate bilayer density, and it is a transmembrane protein. Polypeptide gp95 has a uniquely high content of complex type oligosaccharides compared to other ciliary glycoproteins, a property which is used for its partial purification and can also serve as a probe for functional identification. The present biochemical characterization of frog gp95 and of its putative homologs from other species may open the way to a future assignment of its role in chemosensory reception.