mLin-7 is localized to the basolateral surface of renal epithelia via its NH(2) terminus

In Caenorhabditis elegans, the basolateral localization of the Let-23 growth factor receptor tyrosine kinase requires the expression of three genes: lin-2, lin-7, and lin-10. Mammalian homologs of these three genes have been identified, and a complex of their protein products exists in mammalian neu...

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Bibliographic Details
Published in:American journal of physiology. Renal physiology 2000-03, Vol.278 (3), p.F464
Main Authors: Straight, S W, Karnak, D, Borg, J P, Kamberov, E, Dare, H, Margolis, B, Wade, J B
Format: Article
Language:English
Subjects:
Animals
Cell Line
Dogs
Epithelium - metabolism
Fluorescent Antibody Technique
Humans
Intracellular Membranes - metabolism
Kidney - cytology
Kidney - metabolism
Membrane Proteins - chemistry
Membrane Proteins - metabolism
Rats
Rats, Sprague-Dawley
Tissue Distribution
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Summary:In Caenorhabditis elegans, the basolateral localization of the Let-23 growth factor receptor tyrosine kinase requires the expression of three genes: lin-2, lin-7, and lin-10. Mammalian homologs of these three genes have been identified, and a complex of their protein products exists in mammalian neurons. In this paper, we examine the interaction of these mammalian proteins in renal epithelia. Coprecipitation experiments demonstrated that mLin-2/CASK binds to mLin-7, and immunofluorescent labeling showed that these proteins colocalized at the basolateral surface of Madin-Darby canine kidney cells and renal epithelia. Although labeling intensity varied markedly among different renal epithelial cells, those cells strongly expressing mLin-7 also showed intense mLin-2/CASK labeling. We have also demonstrated that mLin-2/CASK binding requires amino acids 12-32 of mLin-7 and have shown that this region of mLin-7 is also necessary for the targeting of mLin-7 to the basolateral surface. Furthermore, the overexpression of mLin-2/CASK mutants in Madin-Darby canine kidney cells caused endogenous mLin-7 to mislocalize. In summary, the NH(2) terminus of mLin-7 is crucial for its basolateral localization, likely through its interaction with mLin-2/CASK.
ISSN:1931-857X
DOI:10.1152/ajprenal.2000.278.3.F464