SKIP, the host target of the Salmonella virulence factor SifA, promotes kinesin-1-dependent vacuolar membrane exchanges

Traffic. 2010 Jul 1;11(7):899-911. doi: 10.1111/j.1600-0854.2010.01069.x. Epub 2010 Apr 6.

Abstract

In Salmonella-infected cells, the bacterial effector SifA forms a functional complex with the eukaryotic protein SKIP (SifA and kinesin-interacting protein). The lack of either partner has important consequences on the intracellular fate and on the virulence of this pathogen. In addition to SifA, SKIP binds the microtubule-based motor kinesin-1. Yet the absence of SifA or SKIP results in an unusual accumulation of kinesin-1 on the bacterial vacuolar membrane. To understand this apparent contradiction, we investigated the interaction between SKIP and kinesin-1 and the function of this complex. We show that the C-terminal RUN (RPIP8, UNC-14 and NESCA) domain of SKIP interacted specifically with the tetratricopeptide repeat (TPR) domain of the kinesin light chain. Overexpression of SKIP induced a microtubule- and kinesin-1-dependent anterograde movement of late endosomal/lysosomal compartments. In infected cells, SifA contributed to the fission of vesicles from the bacterial vacuole and the SifA/SKIP complex was required for the formation and/or the anterograde transport of kinesin-1-enriched vesicles. These observations reflect the role of SKIP as a linker and/or an activator for kinesin-1.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing / metabolism*
  • Bacterial Proteins / metabolism*
  • Endosomes / metabolism
  • Glycoproteins / metabolism*
  • HeLa Cells
  • Humans
  • Kinesins / metabolism*
  • Microtubules / metabolism
  • Salmonella / metabolism
  • Salmonella / pathogenicity*
  • Salmonella Infections / metabolism
  • Vacuoles / metabolism*
  • Vacuoles / microbiology
  • Virulence
  • Virulence Factors / metabolism

Substances

  • Adaptor Proteins, Signal Transducing
  • Bacterial Proteins
  • Glycoproteins
  • KIF5B protein, human
  • SPHKAP protein, human
  • SifA protein, Salmonella
  • Virulence Factors
  • Kinesins