Identification of a large complex containing the integrin α6β1 laminin receptor in neural retinal cells

Ivan De Curtis, Giuliana Gatti

Research output: Contribution to journalArticlepeer-review

Abstract

Integrin α6β1 is a laminin receptor involved in adhesion and neurite extension of retinal neurons on laminin The present study was carried out to identify potential interactions between the α6β1 receptor and cellular proteins that may be involved in integrin signaling and function For this purpose we have used a biochemical approach based on the solubilization of retinal neurons cultured on laminin with nonionic detergents, followed by centrifugation on sucrose velocity gradients. Analysis of the distribution of the α6 and β1 integrin subunits in the gradients showed that they migrate as a large complex after extraction of cells with octylglucoside, but not after Triton X-100 extraction. Cytoskeletal proteins known to localize in adhesion plaques did not comigrate with α6β1 in octylglucoside gradients, while a set of polypeptides whose tyrosine phosphorylation was enhanced by culture on laminin colocalized with α6β1 on the gradients after octylglucoside solubilization. Culture of retinal neurons on bovine serum albumin, a nonadhesive substratum, partially affected the gradient distribution of the receptor after octylglucoside extraction. Furthermore, analysis of the gradient distribution of two alternatively spliced isoforms of the α6 subunit, α6-cytoA and α6-cytoB, showed that the effect of non-adhesion on the sedimentation properties of the two integrin α6 isoforms was more dramatic for (α6-cytoB than α6-cytoA. These differences in the sedimentation behaviour indicate distinct biochemical properties of the two α6 isoforms that, together with previous observations on their differential distribution in the developing retina, may reflect functional specificities.

Original languageEnglish
Pages (from-to)3165-3172
Number of pages8
JournalJournal of Cell Science
Volume107
Issue number11
Publication statusPublished - Nov 1994

Keywords

  • Laminin receptor
  • Protein complex
  • Retinal neuron

ASJC Scopus subject areas

  • Cell Biology

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