MLC1 is associated with the dystrophin-glycoprotein complex at astrocytic endfeet

Acta Neuropathol. 2007 Oct;114(4):403-10. doi: 10.1007/s00401-007-0247-0. Epub 2007 Jul 13.

Abstract

Megalencephalic leukoencephalopathy with subcortical cysts (MLC) is a progressive cerebral white matter disease with onset in childhood, caused by mutations in the MLC1 gene. MLC1 is a protein with unknown function that is mainly expressed in the brain in astrocytic endfeet at the blood-brain and cerebrospinal fluid-brain barriers. It shares its localization at astrocytic endfeet with the dystrophin-associated glycoprotein complex (DGC). The objective of the present study was to investigate the possible association of MLC1 with the DGC. To test this hypothesis, (co)-localization of DGC-proteins and MLC1 was analyzed by immunohistochemical stainings in gliotic brain tissue from a patient with multiple sclerosis, in glioblastoma tissue and in brain tissue from an MLC patient. In control tissue, a direct protein interaction was tested by immunoprecipitation. Results revealed that MLC1 is co-localized with DGC-proteins in gliotic brain tissue. We demonstrated that both MLC1 and aquaporin-4, a member of the DGC, were redistributed in glioblastoma cells. In MLC brain tissue, we showed absence of MLC1 and altered expression of several DGC-proteins. We demonstrated a direct protein interaction between MLC1 and Kir4.1. From these results we conclude that MLC1 is associated with the DGC at astrocytic endfeet.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aquaporin 4 / metabolism
  • Astrocytes / metabolism*
  • Astrocytes / pathology
  • Blotting, Western
  • Brain / metabolism*
  • Brain / pathology
  • Brain Neoplasms / metabolism
  • Central Nervous System Cysts / metabolism*
  • Central Nervous System Cysts / pathology
  • Dystrophin-Associated Protein Complex / metabolism*
  • Glioma / metabolism
  • Glycoproteins / metabolism
  • Heredodegenerative Disorders, Nervous System / metabolism*
  • Heredodegenerative Disorders, Nervous System / pathology
  • Humans
  • Immunohistochemistry
  • Immunoprecipitation
  • Membrane Proteins / metabolism*
  • Multiple Sclerosis / metabolism
  • Potassium Channels, Inwardly Rectifying / metabolism

Substances

  • AQP4 protein, human
  • Aquaporin 4
  • Dystrophin-Associated Protein Complex
  • Glycoproteins
  • Kcnj10 (channel)
  • MLC1 protein, human
  • Membrane Proteins
  • Potassium Channels, Inwardly Rectifying