Radial Spoke Head 9 Homolog (RSPH9)

Radial spokes are regularly spaced along cilia, sperm, and flagella axonemes and have a multisubunit 'stalk' and 'head' that form a signal transduction scaffold between the central microtubule pair and dynein arms. RSPH9 is predicted to be a component of the radial spoke head based on homology with proteins in the biflagellate alga Chlamydomonas reinhardtii and other ciliates.

The deduced RSPH9 protein contains 276 amino acids and shares 28% identity with the Chlamydomonas radial spoke head protein Rsp9. In situ hybridization of mouse embryos showed Rsph9 expression at the node at embryonic day 7.5 and in nasal, lung, trachea, and brain ventricle epithelium at embryonic days 18.5 and 19.5.