Tubulin transport by IFT is upregulated during ciliary growth by a cilium-autonomous mechanism

Craft, Julie M.; Harris, J. Aaron; Hyman, Sebastian; Kner, Peter; Lechtreck, Karl‐Ferdinand

doi:10.1083/jcb.201409036

Cited by 197 publications

(339 citation statements)

References 78 publications

Supporting

Mentioning

312

Contrasting

Unclassified

Order By: Relevance

“…αβ‐tubulin assembles the backbone of the MT‐based axoneme of the cilium and is a known IFT cargo (Craft et al , 2015) that associates directly with IFT81/74 of the IFT‐B1 subcomplex (Bhogaraju et al , 2013a). The CH domain of IFT81 binds the globular part of αβ‐tubulin ( K d = 16 μM), and mutations of tubulin‐binding residues significantly impair ciliogenesis in human cells (Bhogaraju et al , 2013a).…”

Section: Discussionmentioning

confidence: 99%

“…The affinity of IFT54/20 for αβ‐tubulin was measured to be 3 μM (Appendix Fig S3A). The concentration of tubulin in the cell body of Chlamydomonas was estimated to be in the double‐digit μM range (Craft et al , 2015), and K d 's of 1–3 μM should thus be sufficient to load tubulin onto IFT complexes in cells. The mechanism by which tubulin cargo loading onto IFT trains is regulated in vivo is currently not known.…”

Section: Discussionmentioning

confidence: 99%

“…To build and maintain a functional cilium, cells rely on intraflagellar transport (IFT; for general reviews, see Ishikawa & Marshall, 2011; Pedersen & Rosenbaum, 2008; Nachury et al , 2010), a bidirectional motility along the MTs of the ciliary axoneme (Kozminski et al , 1993). IFT in Chlamydomonas reinhardtii is dependent on the heterotrimeric kinesin II motor to transport ciliary cargo from the cell body to the tip of the cilium (anterograde IFT) (Kozminski et al , 1995; Cole et al , 1998; Qin et al , 2004; Hao et al , 2011; Craft et al , 2015), but in C. elegans and most likely also vertebrate cilia the heterotrimeric kinesin II cooperates with a homodimeric kinesin II motor for anterograde transport (Snow et al , 2004; Williams et al , 2014; Prevo et al , 2015). At the ciliary tip, exchange of the cargo and remodeling of the IFT complex take place and dynein 2 transports the IFT complex and recycling products back to the cell body (retrograde IFT) (Pazour et al , 1999; Porter et al , 1999; Signor et al , 1999; Qin et al , 2004).…”

Section: Introductionmentioning

confidence: 99%

“…However, several ciliary proteins have been shown to move inside cilia with the velocity of IFT and thus likely associate with IFT complexes. These include tubulin, the main axonemal building block, which is a cargo for IFT in both Chlamydomonas reinhardtii (Cr) (Craft et al , 2015) and C. elegans (Hao et al , 2011). In vitro studies suggested that tubulin cargo directly binds to the IFT complex via a dedicated module consisting of a calponin homology (CH) domain of IFT81 and a highly basic domain of IFT74 (Bhogaraju et al , 2013a).…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Intraflagellar transport proteins 172, 80, 57, 54, 38, and 20 form a stable tubulin‐binding IFT‐B2 complex

et al. 2016

View full text Add to dashboard Cite

Intraflagellar transport (IFT) relies on the IFT complex and is required for ciliogenesis. The IFT‐B complex consists of 9–10 stably associated core subunits and six “peripheral” subunits that were shown to dissociate from the core structure at moderate salt concentration. We purified the six “peripheral” IFT‐B subunits of Chlamydomonas reinhardtii as recombinant proteins and show that they form a stable complex independently of the IFT‐B core. We suggest a nomenclature of IFT‐B1 (core) and IFT‐B2 (peripheral) for the two IFT‐B subcomplexes. We demonstrate that IFT88, together with the N‐terminal domain of IFT52, is necessary to bridge the interaction between IFT‐B1 and B2. The crystal structure of IFT52N reveals highly conserved residues critical for IFT‐B1/IFT‐B2 complex formation. Furthermore, we show that of the three IFT‐B2 subunits containing a calponin homology (CH) domain (IFT38, 54, and 57), only IFT54 binds αβ‐tubulin as a potential IFT cargo, whereas the CH domains of IFT38 and IFT57 mediate the interaction with IFT80 and IFT172, respectively. Crystal structures of IFT54 CH domains reveal that tubulin binding is mediated by basic surface‐exposed residues.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Intraflagellar transport proteins 172, 80, 57, 54, 38, and 20 form a stable tubulin‐binding IFT‐B2 complex

et al. 2016

View full text Add to dashboard Cite

show abstract

“…Reduced levels of mutant protein in aged animals via increased UPS activity, coupled with chaperone-mediated stabilization of the complex or folding intermediates enables productive IFT and AdCR in IFT hypomorphic mutant animals ( S6 Fig). HSF-1/Hsp90 and UPS may also indirectly affect IFT to improve ciliogenesis. Hsp90 has been suggested to facilitate tubulin polymerization [81,82]; increased tubulin assembly mediated by Hsp90 may also promote productive IFT [83] in aged IFT hypomorphic mutant backgrounds.…”

Section: Discussionmentioning

confidence: 99%

Structural and Functional Recovery of Sensory Cilia in C. elegans IFT Mutants upon Aging

Maurya

Cornils

Tereshko

et al. 2017

Mechanisms of Development

View full text Add to dashboard Cite

The majority of cilia are formed and maintained by the highly conserved process of intraflagellar transport (IFT). Mutations in IFT genes lead to ciliary structural defects and systemic disorders termed ciliopathies. Here we show that the severely truncated sensory cilia of hypomorphic IFT mutants in C. elegans transiently elongate during a discrete period of adult aging leading to markedly improved sensory behaviors. Age-dependent restoration of cilia morphology occurs in structurally diverse cilia types and requires IFT. We demonstrate that while DAF-16/FOXO is dispensable, the age-dependent suppression of cilia phenotypes in IFT mutants requires cell-autonomous functions of the HSF1 heat shock factor and the Hsp90 chaperone. Our results describe an unexpected role of early aging and protein quality control mechanisms in suppressing ciliary phenotypes of IFT mutants, and suggest possible strategies for targeting subsets of ciliopathies. Author SummaryCilia are 'antenna-like' structures that are present on nearly all cell types in animals. These structures are important for sensing and signaling external cues to the cell. Most cilia are formed by a protein transport process called 'intraflagellar transport' or IFT. Mutations in IFT genes result in severe cilia defects, and are causal to a large number of diverse human disorders called ciliopathies. Since the genes and processes by which cilia are formed are similar across species, studies in experimental models such as the nematode C. elegans can greatly inform our overall understanding of cilia formation and function. Here we report the surprising observation that the structures and functions of severely defective cilia in nematodes with disrupted IFT genes markedly improve upon aging. We find that protein quality control mechanisms that normally decline in aging are required for this age-dependent recovery of cilia structure. Our results raise the possibility that the effects of some mutations in IFT genes can be bypassed under specific conditions, thereby restoring cilia functions.

show abstract

In vivo analyses of radial spoke transport, assembly, repair and maintenance

et al. 2018

Self Cite

View full text Add to dashboard Cite

Radial spokes (RSs) are multiprotein complexes that regulate dynein activity. In the cell body, RS proteins (RSPs) are present in a 12S precursor, which enters the flagella and converts into the axoneme-bound 20S spokes consisting of a head and stalk. To study RS dynamics in vivo, we expressed fluorescent protein (FP)-tagged versions of the head protein RSP4 and the stalk protein RSP3 to rescue the corresponding Chlamydomonas mutants pf1, lacking spoke heads, and pf14, lacking RSs entirely. RSP3 and RSP4 mostly co-migrated by intraflagellar transport (IFT). The transport was elevated during flagellar assembly and IFT of RSP4-FP depended on RSP3. To study RS assembly independently of ciliogenesis, strains expressing FP-tagged RSPs were mated to untagged cells with, without, or with partial RSs. Tagged RSPs were incorporated in a spotted fashion along wild-type-derived flagella indicating an exchange of RSs. During the repair of pf1-derived axonemes, RSP4-FP is added onto the preexisting spoke stalks with little exchange of RSP3. Thus, RSP3 and RSP4 are transported together but appear to separate inside flagella during the repair of RSs. The 12S RS precursor encompassing both proteins could represent a transport form to ensure stoichiometric delivery of RSPs into flagella by IFT.

show abstract

Tubulin transport by IFT is upregulated during ciliary growth by a cilium-autonomous mechanism

Abstract: In Chlamydomonas cilia, IFT concentrates soluble tubulin by regulating IFT train occupancy and thereby promotes elongation of axonemal microtubules.

Cited by 197 publications

References 78 publications

Intraflagellar transport proteins 172, 80, 57, 54, 38, and 20 form a stable tubulin‐binding IFT‐B2 complex

Intraflagellar transport proteins 172, 80, 57, 54, 38, and 20 form a stable tubulin‐binding IFT‐B2 complex

Structural and Functional Recovery of Sensory Cilia in C. elegans IFT Mutants upon Aging

In vivo analyses of radial spoke transport, assembly, repair and maintenance

Contact Info

Product

Resources

About