title: Vimentin and the K-Ras-induced actin-binding protein control inositol-(1,4,5)-trisphosphate receptor redistribution during MDCK cell differentiation.
abstract: Inositol-(1,4,5)-triphosphate receptors (InsP(3)Rs) are ligand-gated Ca(2+) channels that control Ca(2+) release from intracellular stores and play a central role in a wide range of cellular responses. In most epithelial cells, InsP(3)Rs are not uniformly distributed within the endoplasmic reticulum (ER) membrane, with the consequence that agonist stimulation results in compartmentalized Ca(2+) signals. Despite these observations, little is known about the mechanisms that regulate the intracellular localization of InsP(3)Rs. Here, we report that exogenously expressed InsP(3)R1-GFP and endogenous InsP(3)R3 interact with the K-Ras-induced actin-binding protein (KRAP) in both differentiated and undifferentiated Madin-Darby canine kidney (MDCK) cells. KRAP mediates InsP(3)R clustering in confluent MDCK cells and functions as an adapter, linking InsP(3)Rs to vimentin intermediate filaments. Upon epithelial differentiation, KRAP and vimentin are both required for InsP(3)R accumulation at the periphery of MDCK cells. Finally, KRAP associates with vimentin in chicken B lymphocytes and with keratins in a breast cancer cell line devoid of vimentin. Collectively, our data suggest that intermediate filaments in conjunction with KRAP may govern the localization of InsP(3)Rs in a large number of cell types (including epithelial cells) and in various physiological or pathological contexts.
authors.affiliation: Laboratory of Proteomic Mass Spectrometry, Institut Curie, 75248 Paris, Cedex 05,  France.
authors.forename: Florent
authors.initials: F
authors.lastname: Dingli
authors.forename: Jan B
authors.initials: JB
authors.lastname: Parys
authors.forename: Damarys
authors.initials: D
authors.lastname: Loew
authors.forename: Simon
authors.initials: S
authors.lastname: Saule
authors.forename: Laurence
authors.initials: L
authors.lastname: Mery
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D016764:Cell Polarity / Q000187:drug effects; D002853:Chromatography, Liquid; D004285:Dogs; D015536:Down-Regulation / Q000187:drug effects; D017353:Gene Deletion; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006801:Humans; D053496:Inositol 1,4,5-Trisphosphate Receptors / Q000378:metabolism*; D007633:Keratins / Q000378:metabolism; D061985:Madin Darby Canine Kidney Cells; D008565:Membrane Proteins / Q000378:metabolism; D008840:Microfilament Proteins / Q000378:metabolism*; D050505:Mutant Proteins / Q000378:metabolism; D017830:Octoxynol / Q000494:pharmacology; D011485:Protein Binding / Q000187:drug effects; D017434:Protein Structure, Tertiary; D021381:Protein Transport / Q000187:drug effects; D034741:RNA, Small Interfering / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D013347:Subcellular Fractions / Q000187:drug effects / Q000378:metabolism; D053719:Tandem Mass Spectrometry; D014746:Vimentin / Q000378:metabolism*; D018631:ras Proteins / Q000378:metabolism*
chemical_list: D053496:Inositol 1,4,5-Trisphosphate Receptors; D008565:Membrane Proteins; D008840:Microfilament Proteins; D050505:Mutant Proteins; D034741:RNA, Small Interfering; D011993:Recombinant Fusion Proteins; D014746:Vimentin; D049452:Green Fluorescent Proteins; D007633:Keratins; D017830:Octoxynol; D018631:ras Proteins