Thy-1 expresses two signals for apical localization in epithelial cells.
Recent work has shown that anchoring via glycosyl phosphatidylinositol (GPI) results in apical targeting for a variety of endogenous and transfected plasma membrane proteins expressed in epithelial cells. To further determine the correlation between GPI anchoring and apical localization, we expressed GPI-anchored and secretory forms of Thy-1 in Madin-Darby canine kidney cells by transfection. Native GPI-anchored Thy-1, normally expressed in thymocytes and neurons, was localized to the apical surface. A truncated form of Thy-1, lacking 22 out of 31 hydrophobic amino acids at the COOH-terminus, was also constructed; this deletion blocked attachment of the GPI anchor and resulted in apical secretion of Thy-1. In combination with previous results, our observations indicate that Thy-1 contains apical targeting information in its protein sequence as well as in the GPI anchor.
Powell
S K
SK
Department of Cell Biology and Anatomy, Cornell University Medical College, New York, New York 10021.
Lisanti
M P
MP
Rodriguez-Boulan
E J
EJ
D000818:Animals; D000954:Antigens, Surface / Q000032:analysis / Q000096:biosynthesis*; D018958:CD55 Antigens; D002460:Cell Line; D002462:Cell Membrane / Q000502:physiology*; D004285:Dogs; D004848:Epithelium / Q000502:physiology; D006017:Glycolipids / Q000502:physiology; D017261:Glycosylphosphatidylinositols; D007668:Kidney; D008565:Membrane Proteins / Q000235:genetics / Q000502:physiology; D008970:Molecular Weight; D010716:Phosphatidylinositols / Q000502:physiology; D015398:Signal Transduction; D018800:Thy-1 Antigens; D014162:Transfection
D000954:Antigens, Surface; D018958:CD55 Antigens; D006017:Glycolipids; D017261:Glycosylphosphatidylinositols; D008565:Membrane Proteins; D010716:Phosphatidylinositols; D018800:Thy-1 Antigens