Unique properties of lamp2a compared to other lamp2 isoforms

A. M. Cuervo, J. F. Dice

Research output: Contribution to journalArticle

184 Scopus citations

Abstract

Lamp2a acts as a receptor in the lysosomal membrane for substrate proteins of chaperone-mediated autophagy. Using antibodies specific for the cytosolic tail of lamp2a and others recognizing all lamp2 isoforms, we found that in rat liver lamp2a represents 25% of lamp2s in the lysosome. We show that lamp2a levels in the lysosomal membrane in rat liver and fibroblasts in culture directly correlate with rates of chaperone-mediated autophagy in a variety of physiological and pathological conditions. The concentration of other lamp2s in the lysosomal membrane show no correlation under the same conditions. Furthermore, substrate proteins bind to lamp2a but not to other lamp2s. Four positively-charged amino acids uniquely present in the cytosolic tail of lamp2a are required for the binding of substrate proteins. Lamp2a also distributes to an unique subpopulation of perinuclear lysosomes in cultured fibroblasts in response to serum withdrawal, and lamp2a, more than other lamp2s, tends to multimerize. These characteristics may be important for lamp2a to act as a receptor for chaperone-mediated autophagy.

Original languageEnglish (US)
Pages (from-to)4441-4450
Number of pages10
JournalJournal of cell science
Volume113
Issue number24
StatePublished - Dec 1 2000
Externally publishedYes

Keywords

  • Chaperone
  • Lysosome
  • Membrane receptor
  • Protein degradation
  • Rat liver

ASJC Scopus subject areas

  • Cell Biology

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