title: The Chlamydomonas reinhardtii BBSome is an IFT cargo required for export of specific signaling proteins from flagella.
abstract: In humans, seven evolutionarily conserved genes that cause the cilia-related disorder Bardet-Biedl syndrome (BBS) encode proteins that form a complex termed the BBSome. The function of the BBSome in the cilium is not well understood. We purified a BBSome-like complex from Chlamydomonas reinhardtii flagella and found that it contains at least BBS1, -4, -5, -7, and -8 and undergoes intraflagellar transport (IFT) in association with a subset of IFT particles. C. reinhardtii insertional mutants defective in BBS1, -4, and -7 assemble motile, full-length flagella but lack the ability to phototax. In the bbs4 mutant, the assembly and transport of IFT particles are unaffected, but the flagella abnormally accumulate several signaling proteins that may disrupt phototaxis. We conclude that the BBSome is carried by IFT but is an adapter rather than an integral component of the IFT machinery. C. reinhardtii BBS4 may be required for the export of signaling proteins from the flagellum via IFT.
authors.affiliation: Department of Cell Biology, University of Massachusetts Medical School, Worcester, 01655, USA. Karl.Lechtreck@umassmed.edu
authors.forename: Karl-Ferdinand
authors.initials: KF
authors.lastname: Lechtreck
authors.forename: Eric C
authors.initials: EC
authors.lastname: Johnson
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Sakai
authors.forename: Deborah
authors.initials: D
authors.lastname: Cochran
authors.forename: Bryan A
authors.initials: BA
authors.lastname: Ballif
authors.forename: John
authors.initials: J
authors.lastname: Rush
authors.forename: Gregory J
authors.initials: GJ
authors.lastname: Pazour
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Ikebe
authors.forename: George B
authors.initials: GB
authors.lastname: Witman
mesh_terms: D020418:Algal Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D054468:Axoneme / Q000235:genetics / Q000502:physiology; D016825:Chlamydomonas reinhardtii / Q000235:genetics / Q000378:metabolism*; D005407:Flagella / Q000378:metabolism*; D021381:Protein Transport / Q000502:physiology; D015398:Signal Transduction
chemical_list: D020418:Algal Proteins