Probable component of the tectonic-like complex (also named MKS complex), a complex localized at the transition zone of primary cilia (PubMed:27577095, PubMed:27646273). Required for ciliary structure and function (PubMed:27577095). Probable component of the tectonic-like complex (also named MKS complex), composed of B9d1, B9d2, Cc2d2a, Mks1 and tctn. Localizes at the transition zone (TZ), a region between the basal body and the ciliary axoneme in the olfactory, auditory and speromatocyte system (PubMed:27646273, PubMed:30013109). In spermatocytes, localizes in the transition zone and the migrating base of the spermatid ciliary cap (PubMed:25447994, PubMed:27577095). Co-localizes with the tectonic-like complex (PubMed:27646273). Expressed in type I sensory neurons (at protein level) (PubMed:22508513, PubMed:30013109). Expressed in spermatids and spermatocytes (at protein level) (PubMed:25447994, PubMed:27646273, PubMed:27577095, PubMed:30013109). Viable and fertile (PubMed:27577095). Results in lack of localization of the tectonic-like module proteins, namely MKS1 and B9d2, to the transition zone resulting in minor defects in sensory cilia (PubMed:27577095). Belongs to the B9D family.