biostudies-literatureHanke-Gogokhia CRetina Research Foundation HoustonHHS NIH National Eye Institute (NEI)NEI NIH HHSResearch to Prevent Blindness (RPB)21442-21456https://www.ebi.ac.uk/biostudies/studies/S-EPMC5766971biostudies-literatureUnknown292(52)Arf-like protein 13b (ARL13b) is a small GTPase that functions as a guanosine nucleotide exchange factor (GEF) for ARL3-GDP. ARL13b is located exclusively in photoreceptor outer segments (OS) presumably anchored to discs by palmitoylation, whereas ARL3 is an inner segment cytoplasmic protein. Hypomorphic mutations affecting the ARL13b G-domain inactivate GEF activity and lead to Joubert syndrome (JS) in humans. However, the molecular mechanisms in ARL13b mutation-induced Joubert syndrome, particularly the function of primary cilia, are still incompletely understood. Because <i>Arl13b</i> germline knockouts in mouse are lethal, we generated retina-specific deletions of ARL13b in which ARL3-GTP formation is impaired. In mouse ^ret<i>Arl13b</i>^-/- central retina at postnaThe Journal of biological chemistryThe guanine nucleotide exchange factor Arf-like protein 13b is essential for assembly of the mouse photoreceptor transition zone and outer segment.PMC5766971graduate student fellowshipEY014800–039003Unrestricted GrantP30 EY014800R01 EY019298EY019298R01 EY008123EY08123T32 EY024234Wu ZSharif ABaehr WFrederick JMHanke-Gogokhia CYazigi HfalseThe guanine nucleotide exchange factor Arf-like protein 13b is essential for assembly of the mouse photoreceptor transition zone and outer segment.Arf-like protein 13b (ARL13b) is a small GTPase that functions as a guanosine nucleotide exchange factor (GEF) for ARL3-GDP. ARL13b is located exclusively in photoreceptor outer segments (OS) presumably anchored to discs by palmitoylation, whereas ARL3 is an inner segment cytoplasmic protein. Hypomorphic mutations affecting the ARL13b G-domain inactivate GEF activity and lead to Joubert syndrome (JS) in humans. However, the molecular mechanisms in ARL13b mutation-induced Joubert syndrome, particularly the function of primary cilia, are still incompletely understood. Because <i>Arl13b</i> germline knockouts in mouse are lethal, we generated retina-specific deletions of ARL13b in which ARL3-GTP formation is impaired. In mouse ^ret<i>Arl13b</i>^-/- central retina at postna2017-01-01T00:00:00Z2017 Dec2025-04-05T11:15:29.269Z2019-03-26T22:33:20ZS-EPMC57669712908938410.1074/jbc.ra117.00014110.1074/jbc.RA117.000141