Different functional recognition of basolateral signals in Caco-2 and MDCK cells.
Using the basolateral mutant PS of the normally apical neurotrophin receptor p75 (p75NTR) we have identified two cytoplasmic determinants responsible for this reversed localization in the human intestinal cell line, Caco2. These signals are based on two consecutive leucines (322-323) and a tyrosine (Y308). Truncation of the cytoplasmic tail removing the two leucines or their replacement by alanines led to a nonpolarized expression of the resulting mutants in Caco2 cells. To our surprise, the same mutations had no effect on the basolateral localization of the mutant PS in MDCK cells. In MDCK cells, the basolateral localization was entirely dependent on a cytoplasmic tyrosine Y308, while in Caco-2 cells this tyrosine signal was functional as a basolateral signal only when the cytoplasmic domain of PS was truncated shortly after it. These data indicate for the first time that there is a differential recognition of basolateral signals between MDCK and Caco-2 cells.
Laboratoire de Génétique et Physiologie du Développement, UMR 6545, IBDM, Faculté des Sciences de Luminy, Université de la Méditerranée, Marseille, France.
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D019943:Amino Acid Substitution; D000818:Animals; D018938:Caco-2 Cells; D002460:Cell Line; D002462:Cell Membrane / Q000502:physiology*; D004285:Dogs; D006801:Humans; D007413:Intestinal Mucosa; D007668:Kidney; D007930:Leucine; D016297:Mutagenesis, Site-Directed; D017475:Receptors, Nerve Growth Factor / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D017384:Sequence Deletion; D015398:Signal Transduction / Q000502:physiology*; D014162:Transfection; D014443:Tyrosine; D019459:Urothelium
D017475:Receptors, Nerve Growth Factor; D011994:Recombinant Proteins; D014443:Tyrosine; D007930:Leucine