BBS9

BBS9 (PTHB1) is a core structural subunit of the BBSome, an octameric coat-like adaptor complex (BBS1, BBS2, BBS4, BBS5, BBS7, BBS8/TTC8, BBS9 and BBIP1/BBIP10) that sorts and traffics specific membrane and signaling-receptor cargo into and out of the primary cilium in conjunction with intraflagellar transport (IFT) and the small GTPase ARL6/BBS3. The N-terminal ~407 residues fold into a seven-bladed beta-propeller, followed by gamma-adaptin-ear (GAE), platform, hairpin and a C-terminal alpha-helical region; together with BBS2 and BBS7, BBS9 forms the central scaffold that organizes the complex. BBSome assembly is chaperonin-assisted (BBS6/BBS10/BBS12 with CCT/TRiC), and BBS9 stability is required for assembly. The protein localizes to nonmembranous centriolar satellites and the pericentriolar region in the cytoplasm and to the ciliary membrane, transition zone and tip. Its ciliary trafficking is regulated by partners including LZTFL1, ARL6/BBS3, AZI1/CEP131 and the NPHP5(IQCB1)/CEP290 module. Loss-of-function mutations (e.g. the destabilizing G141R variant) cause autosomal-recessive Bardet-Biedl syndrome, a ciliopathy featuring retinal degeneration, obesity, polydactyly, hypogenitalism, renal anomalies and cognitive impairment.

Disorders

Relationship is the entry's genetic[].relationship_type. untyped means the entry has a genetic record for the gene but does not type it; its free-text association is shown instead.

An entry matches when ClinGen's MONDO disease is the entry's own disease term, a subtype term, or an exact-match mapping. An amber status marks an entry ClinGen supports the gene for (Definitive, Strong or Moderate) whose own record does not type it. A Limited, Disputed or Refuted tier on such an entry is not a gap.

• bbsome_trafficking via Bardet-Biedl syndrome, BBSome-related retinitis pigmentosa