Photoreceptor IFT complexes containing chaperones, guanylyl cyclase 1 and rhodopsin

Reshma Bhowmick, Mei Li, Jun Sun, Sheila A. Baker, Christine Insinna, Joseph C. Besharse*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

56 Scopus citations


Intraflagellar transport (IFT) provides a mechanism for the transport of cilium-specific proteins, but the mechanisms for linkage of cargo and IFT proteins have not been identified. Using the sensory outer segments (OS) of photoreceptors, which are derived from sensory cilia, we have identified IFT-cargo complexes containing IFT proteins, kinesin 2 family proteins, two photoreceptor-specific membrane proteins, guanylyl cyclase 1 (GC1, Gucy2e) and rhodopsin (RHO), and the chaperones, mammalian relative of DNAJ, DnajB6 (MRJ), and HSC70 (Hspa8). Analysis of these complexes leads to a model in which MRJ through its binding to IFT88 and GC1 plays a critical role in formation or stabilization of the IFT-cargo complexes. Consistent with the function of MRJ in the activation of HSC70 ATPase activity, Mg-ATP enhances the co-IP of GC1, RHO, and MRJ with IFT proteins. Furthermore, RNAi knockdown of MRJ in IMCD3 cells expressing GC1-green fluorescent protein (GFP) reduces cilium membrane targeting of GC1-GFP without apparent effect on cilium elongation.

Original languageEnglish (US)
Pages (from-to)648-663
Number of pages16
Issue number6
StatePublished - 2009


  • Cilium
  • HSC70
  • IFT
  • Kinesin 2
  • MRJ
  • Membrane guanylyl cyclase
  • Photoreceptor
  • Rhodopsin

ASJC Scopus subject areas

  • Genetics
  • Molecular Biology
  • Structural Biology
  • Biochemistry
  • Cell Biology


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