A Role of the Lowe Syndrome Protein OCRL in Early Steps of the Endocytic Pathway

Dev Cell. 2007 Sep;13(3):377-90. doi: 10.1016/j.devcel.2007.08.004.

Abstract

Mutations in the inositol 5-phosphatase OCRL are responsible for Lowe syndrome, whose manifestations include mental retardation and renal Fanconi syndrome. OCRL has been implicated in membrane trafficking, but disease mechanisms remain unclear. We show that OCRL visits late-stage, endocytic clathrin-coated pits and binds the Rab5 effector APPL1 on peripheral early endosomes. The interaction with APPL1, which is mediated by the ASH-RhoGAP-like domains of OCRL and is abolished by disease mutations, provides a link to protein networks implicated in the reabsorptive function of the kidney and in the trafficking and signaling of growth factor receptors in the brain. Crystallographic studies reveal a role of the ASH-RhoGAP-like domains in positioning the phosphatase domain at the membrane interface and a clathrin box protruding from the RhoGAP-like domain. Our results support a role of OCRL in the early endocytic pathway, consistent with the predominant localization of its preferred substrates, PI(4,5)P(2) and PI(3,4,5)P(3), at the cell surface.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing
  • Amino Acid Sequence
  • Animals
  • COS Cells
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism
  • Cell Line
  • Chlorocebus aethiops
  • Clathrin-Coated Vesicles / metabolism
  • Crystallography, X-Ray
  • Endocytosis / physiology*
  • Endosomes / enzymology
  • Endosomes / metabolism*
  • Glutathione Transferase / metabolism
  • Green Fluorescent Proteins / metabolism
  • Humans
  • Kidney / cytology
  • Models, Biological
  • Models, Molecular
  • Molecular Sequence Data
  • Mutation
  • Phosphatidylinositol 4,5-Diphosphate / metabolism
  • Phosphatidylinositols / metabolism
  • Phosphoric Monoester Hydrolases / chemistry
  • Phosphoric Monoester Hydrolases / genetics
  • Phosphoric Monoester Hydrolases / isolation & purification
  • Phosphoric Monoester Hydrolases / metabolism*
  • Phosphorylation
  • Protein Structure, Secondary
  • Protein Structure, Tertiary
  • Recombinant Fusion Proteins / metabolism
  • Sequence Homology, Amino Acid
  • Time Factors

Substances

  • APPL1 protein, human
  • Adaptor Proteins, Signal Transducing
  • Carrier Proteins
  • Phosphatidylinositol 4,5-Diphosphate
  • Phosphatidylinositols
  • Recombinant Fusion Proteins
  • phosphoinositide-3,4,5-triphosphate
  • Green Fluorescent Proteins
  • Glutathione Transferase
  • Phosphoric Monoester Hydrolases
  • OCRL protein, human

Associated data

  • PDB/2QV2