1. Academic Validation
  2. Disruption of intraflagellar protein transport in photoreceptor cilia causes Leber congenital amaurosis in humans and mice

Disruption of intraflagellar protein transport in photoreceptor cilia causes Leber congenital amaurosis in humans and mice

  • J Clin Invest. 2011 Jun;121(6):2169-80. doi: 10.1172/JCI45627.
Karsten Boldt 1 Dorus A Mans Jungyeon Won Jeroen van Reeuwijk Andreas Vogt Norbert Kinkl Stef J F Letteboer Wanda L Hicks Ron E Hurd Jürgen K Naggert Yves Texier Anneke I den Hollander Robert K Koenekoop Jean Bennett Frans P M Cremers Christian J Gloeckner Patsy M Nishina Ronald Roepman Marius Ueffing
Affiliations

Affiliation

  • 1 Division of Experimental Ophthalmology and Medical Proteome Center, Center of Ophthalmology, University of Tübingen, Tübingen, Germany.
Abstract

The mutations that cause Leber congenital amaurosis (LCA) lead to photoreceptor cell death at an early age, causing childhood blindness. To unravel the molecular basis of LCA, we analyzed how mutations in LCA5 affect the connectivity of the encoded protein lebercilin at the interactome level. In photoreceptors, lebercilin is uniquely localized at the cilium that bridges the inner and outer segments. Using a generally applicable affinity proteomics approach, we showed that lebercilin specifically interacted with the intraflagellar transport (IFT) machinery in HEK293T cells. This interaction disappeared when 2 human LCA-associated lebercilin mutations were introduced, implicating a specific disruption of IFT-dependent protein transport, an evolutionarily conserved basic mechanism found in all cilia. Lca5 inactivation in mice led to partial displacement of opsins and light-induced translocation of Arrestin from photoreceptor outer segments. This was consistent with a defect in IFT at the connecting cilium, leading to failure of proper outer segment formation and subsequent photoreceptor degeneration. These data suggest that lebercilin functions as an integral element of selective protein transport through photoreceptor cilia and provide a molecular demonstration that disrupted IFT can lead to LCA.

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