The GTPase IFT27 is involved in both anterograde and retrograde intraflagellar transport

Elife. 2014 Apr 24:3:e02419. doi: 10.7554/eLife.02419.

Abstract

The construction of cilia and flagella depends on intraflagellar transport (IFT), the bidirectional movement of two protein complexes (IFT-A and IFT-B) driven by specific kinesin and dynein motors. IFT-B and kinesin are associated to anterograde transport whereas IFT-A and dynein participate to retrograde transport. Surprisingly, the small GTPase IFT27, a member of the IFT-B complex, turns out to be essential for retrograde cargo transport in Trypanosoma brucei. We reveal that this is due to failure to import both the IFT-A complex and the IFT dynein into the flagellar compartment. To get further molecular insight about the role of IFT27, GDP- or GTP-locked versions were expressed in presence or absence of endogenous IFT27. The GDP-locked version is unable to enter the flagellum and to interact with other IFT-B proteins and its sole expression prevents flagellum formation. These findings demonstrate that a GTPase-competent IFT27 is required for association to the IFT complex and that IFT27 plays a role in the cargo loading of the retrograde transport machinery.DOI: http://dx.doi.org/10.7554/eLife.02419.001.

Keywords: IFT; Trypanosoma brucei; flagellum; small GTPase.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Biological Transport
  • Cell Line
  • Cilia / genetics
  • Cilia / metabolism
  • Dyneins / genetics
  • Dyneins / metabolism
  • Flagella / genetics
  • Flagella / metabolism
  • GTP Phosphohydrolases / genetics*
  • GTP Phosphohydrolases / metabolism
  • Gene Expression Regulation
  • Gene Silencing
  • Kinesins / genetics
  • Kinesins / metabolism
  • Mice
  • Mice, Inbred BALB C
  • Molecular Sequence Data
  • Point Mutation
  • Protozoan Proteins / genetics*
  • Protozoan Proteins / metabolism
  • RNA Interference
  • Sequence Alignment
  • Trypanosoma brucei brucei / genetics*
  • Trypanosoma brucei brucei / metabolism
  • rab GTP-Binding Proteins / genetics*
  • rab GTP-Binding Proteins / metabolism

Substances

  • Protozoan Proteins
  • GTP Phosphohydrolases
  • Dyneins
  • Kinesins
  • rab GTP-Binding Proteins

Grants and funding

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.