Tyrosine-based membrane protein sorting signals are differentially interpreted by polarized Madin-Darby canine kidney and LLC-PK1 epithelial cells

Denise L. Roush, Cara J. Gottardi, Hussein Y. Naim, Michael G. Roth, Michael J. Caplan*

*Corresponding author for this work

Research output: Contribution to journalArticle

98 Scopus citations

Abstract

Tyrosine-dependent sequence motifs are implicated in sorting membrane proteins to the basolateral domain of Madin-Darby canine kidney (MDCK) cells. We find that these motifs are interpreted differentially in various polarized epithelial cell types. The H,K-ATPase β subunit, which contains a tyrosine- based motif in its cytoplasmic tail, was expressed in MDCK and LLC-PK1 cells. This protein was restricted to the basolateral membrane in MDCK cells, but was localized to the apical membrane in LLC-PK1 cells. Similarly, HA- Y543, a construct in which a tyrosine-based motif was introduced into the cytoplasmic tail of influenza hemagglutinin, was sorted to the basolateral membrane of MDCK cells and retained at the apical membrane of LLC-PK1 cells. A chimera in which the cytoplasmic tail of the H,K-ATPase β subunit protein was replaced with the analogous region of the Na,K-ATPase β subunit polypeptide was localized to both surface domains of MDCK cells. Mutation of tyrosine-20 of the H,K-ATPase β subunit cytoplasmic sequence to an alanine was SUfficient to disrupt basolateral localization of this polypeptide. In contrast, these constructs all remain localized to the apical membrane in LLC-PK1 cells. The FcRII-B2 protein bears a di-leucine motif and is found at the basolateral membrane of both MDCK and LLC-PK1 cells. These results demonstrate that polarized epithelia are able to discriminate between different classes of specifically defined membrane protein sorting signals.

Original languageEnglish (US)
Pages (from-to)26862-26869
Number of pages8
JournalJournal of Biological Chemistry
Volume273
Issue number41
DOIs
StatePublished - Oct 9 1998

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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