Dynamics of endogenous ATP7A (Menkes protein) in intestinal epithelial cells: Copper-dependent redistribution between two intracellular sites

L. Nyasae, R. Bustos, L. Braiterman, B. Eipper, A. Hubbard

Research output: Contribution to journalArticlepeer-review

Abstract

We report for the first time on the copper-dependent behavior of endogenous ATP7A in two types of polarized intestinal epithelia, rat enterocytes in vivo and filter-grown Caco-2 cells, an accepted in vitro model of human small intestine. We used high-resolution, confocal immunofluorescence combined with quantitative cell surface biotinylation and found that the vast majority of endogenous ATP7A was localized intracellularly under all copper conditions. In copper-depleted cells, virtually all of the ATP7A localized to a post-TGN compartment, with <3% of the total protein detectable at the basolateral cell surface. When copper levels were elevated, ATP7A dispersed to the cell periphery in punctae whose pattern did not overlap with the steady-state distributions of post-Golgi, endosomal, or basolateral membrane markers; only ̃8-10% of the recovered ATP7A was detected at the basolateral cell surface. These results raise several questions regarding prevailing models of ATP7A dynamics and the mechanism of copper efflux.

Original languageEnglish (US)
Pages (from-to)G1181-G1194
JournalAmerican Journal of Physiology - Gastrointestinal and Liver Physiology
Volume292
Issue number4
DOIs
StatePublished - Apr 2007

Keywords

  • Biotinylation
  • Caco-2
  • Intestine
  • Trafficking

ASJC Scopus subject areas

  • Physiology
  • Hepatology
  • Gastroenterology
  • Physiology (medical)

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