HUMAN SYNTAXIN-3 IS LOCALIZED APICALLY IN HUMAN INTESTINAL-CELLS

To understand the molecular mechanisms underlying sorting of apical an d basolateral membrane components in human intestinal epithelial cells , we have cloned the human homolog of rat syntaxin 3 and looked for it s subcellular localization. Endogenous human syntaxin 3 was found to b e localized at the apical membrane of colon epithelial and Caco-2 cell s. This apical localization was confirmed by confocal microscopy after transfection of the cDNA coding for either full length or N-terminall y truncated human syntaxin 3 in Caco-2 cells. Furthermore the signal(s ) and machinery targeting human syntaxin 3 to the apical membrane of e pithelial cells are conserved between species since human syntaxin 3 w as also localized at the apical membrane of canine MDCK cells and of e pithelial cells in transgenic Drosophila melanogaster.