Receptor tyrosine phosphatase R-PTP-kappa mediates homophilic binding.
Receptor tyrosine phosphatases (R-PTPases) feature PTPase domains in the context of a receptor-like transmembrane topology. The R-PTPase R-PTP-kappa displays an extracellular domain composed of fibronectin type III motifs, a single immunoglobulin domain, as well as a recently defined MAM domain (Y.-P. Jiang, H. Wang, P. D'Eustachio, J.M. Musacchio, J. Schlessinger, and J. Sap, Mol. Cell. Biol. 13:2942-2951, 1993). We report here that R-PTP-kappa can mediate homophilic intercellular interaction. Inducible expression of the R-PTP-kappa protein in heterologous cells results in formation of stable cellular aggregates strictly consisting of R-PTP-kappa-expressing cells. Moreover, the purified extracellular domain of R-PTP-kappa functions as a substrate for adhesion by cells expressing R-PTP-kappa and induces aggregation of coated synthetic beads. R-PTP-kappa-mediated intercellular adhesion does not require PTPase activity or posttranslational proteolytic cleavage of the R-PTP-kappa protein and is calcium independent. The results suggest that R-PTPases may provide a link between cell-cell contact and cellular signaling events involving tyrosine phosphorylation.
Sap
J
J
Department of Pharmacology, New York University Medical Center, New York 10016.
Jiang
Y P
YP
Friedlander
D
D
Grumet
M
M
Schlessinger
J
J
D000818:Animals; D002448:Cell Adhesion / Q000502:physiology; D002449:Cell Aggregation / Q000502:physiology; D002450:Cell Communication / Q000502:physiology; D002460:Cell Line; D018076:DNA, Complementary / Q000235:genetics; D004331:Drosophila melanogaster; D005110:Extracellular Space / Q000378:metabolism; D015870:Gene Expression; D006801:Humans; D051379:Mice; D011487:Protein Conformation; D017027:Protein Tyrosine Phosphatases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D054623:Receptor-Like Protein Tyrosine Phosphatases, Class 2; D011994:Recombinant Proteins / Q000378:metabolism; D014162:Transfection
D018076:DNA, Complementary; D011994:Recombinant Proteins; C489852:PTPRK protein, human; D017027:Protein Tyrosine Phosphatases; C080778:Ptprk protein, mouse; D054623:Receptor-Like Protein Tyrosine Phosphatases, Class 2