Referenced in: none

Automatically associated channels: Kv6.1

Title: Specific interaction between lens MIP/Aquaporin-0 and two members of the gamma-crystallin family.

Authors: Jianguo Fan, Robert N Fariss, Andrew G Purkiss, Christine Slingsby, Aileen Sandilands, Roy Quinlan, Graeme Wistow, Ana B Chepelinsky

Journal, date & volume: Mol. Vis., 2005 Jan 25 , 11, 76-87

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/15692460

Abstract
Major Intrinsic Protein (MIP)/Aquaporin 0 is required for lens transparency and is specifically expressed in lens fiber cell membranes. We have demonstrated previously that in the rat lens MIP interacts specifically with gammaE-crystallin, resulting in its recruitment to the plasma membrane. Our goal was to examine the interaction or lack of interaction between MIP and all members of the gamma-crystallin family and to provide evidence for a physiological role these interactions may play in gamma-crystallin or MIP function.Full length MIP was expressed as untagged, enhanced green fluorescent protein (EGFP) tagged, or myc tagged proteins. Members of the gamma-crystallin family were expressed as red fluorescent protein (HcRed) tagged proteins in the rabbit kidney epithelial cell line RK13. Co-localization of tagged proteins was analyzed by confocal fluorescence microscopy.Confocal fluorescence microscopy demonstrated that gammaE- and gammaF-crystallin co-localize specifically with full length MIP in mammalian cells while other gamma-crystallins, including gammaA-, gammaB-, gammaC-, gammaD-, and gammaS-crystallin do not. As a result of this interaction, either gammaE- or gammaF-crystallin was recruited to the plasma membrane from the cytoplasm. MIP does not interact with the Elo mutant of gammaE-crystallin, which has been linked to a dominant cataract phenotype in mice.These experiments demonstrate that MIP interacts selectively with gammaE- and gammaF-crystallin, and not with other gamma-crystallins. This raises the possibility of MIP playing a structural role in the organization of gamma-crystallins in rodent lens fibers and/or that gammaE- and gammaF-crystallin may have a specific role in MIP function in the rodent lens.