A dileucine motif targets MCAM-l cell adhesion molecule to the basolateral membrane in MDCK cells.
Melanoma cell adhesion molecule (MCAM), an adhesion molecule belonging to the Ig superfamily, is an endothelial marker and is expressed in different epithelia. MCAM is expressed as two isoforms differing by their cytoplasmic domain: MCAM-l and MCAM-s (long and short). In order to identify the respective role of each MCAM isoform, we analyzed MCAM isoform targeting in polarized epithelial Madin-Darby canine kidney (MDCK) cells using MCAM-GFP chimeras. Confocal microscopy revealed that MCAM-s and MCAM-l were addressed to the apical and basolateral membranes, respectively. Transfection of MCAM-l mutants established that a single dileucine motif (41-42) of the cytoplasmic domain was required for MCAM-l basolateral targeting in MDCK cells. Although double labelling experiments showed that MCAM-l is not a component of adherens junctions and focal adhesions, its expression on basolateral membranes suggests that MCAM-l is involved in epithelium insuring.
Guezguez
Borhane
B
Université Pierre et Marie, Curie-Paris 6, CNRS UMR 7622, Bat C 6ème étage, Case 24, 9 quai Saint-Bernard, 75252 Paris Cedex 05, France.
Vigneron
Pascale
P
Alais
Sandrine
S
Jaffredo
Thierry
T
Gavard
Julie
J
Mège
René-Marc
RM
Dunon
Dominique
D
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D002448:Cell Adhesion; D015815:Cell Adhesion Molecules / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism*; D016764:Cell Polarity; D021982:Cell-Matrix Junctions; D002645:Chickens; D003593:Cytoplasm / Q000378:metabolism; D004285:Dogs; D006801:Humans; D008969:Molecular Sequence Data; D016415:Sequence Alignment
D015815:Cell Adhesion Molecules