Complete and partial glycophospholipid anchors are found on a fusion protein consisting of luteinizing hormone beta subunit followed by a carboxyl-terminal domain of Thy-1.
The Thy-1 antigen is anchored to the cell surface by a carboxyl-terminal glycophospholipid moiety. To investigate the extent of anchor addition which occurs when such proteins cannot move efficiently to the cell surface, we have expressed a recombinant fusion protein composed of 107 amino-terminal amino acids of bovine luteinizing hormone beta subunit and 46 COOH-terminal amino acids of murine Thy-1 (Thy-1.2 allele). Although the limited amount of fusion protein transported to the cell surface is glycophospholipid-anchored, most of the protein accumulates in an intracellular, endoglycosidase H-sensitive form. The intracellular protein has an unusual structure that contains ethanolamine but does not bind detergent, suggesting either that anchor addition proceeds via a hydrophilic partial intermediate, or that anchor-degradative enzymes exist along the secretory path.
Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106.
D M
DM
Kaetzel
N
N
Singh
G C
GC
Kennedy
J B
JB
Virgin
G
G
Farr
Y
Y
Kitagawa
J H
JH
Nilson
A M
AM
Tartakoff
D000818:Animals; D000954:Antigens, Surface / Q000235:genetics* / Q000302:isolation & purification; D001358:Avian Sarcoma Viruses / Q000235:genetics; D002417:Cattle; D002460:Cell Line; D002462:Cell Membrane / Q000276:immunology / Q000648:ultrastructure; D019856:Ethanolamine; D004983:Ethanolamines / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D005822:Genetic Vectors; D006017:Glycolipids / Q000032:analysis*; D015292:Glycoprotein Hormones, alpha Subunit / Q000235:genetics* / Q000302:isolation & purification; D017261:Glycosylphosphatidylinositols; D010716:Phosphatidylinositols / Q000032:analysis*; D011993:Recombinant Fusion Proteins / Q000302:isolation & purification; D018800:Thy-1 Antigens; D014162:Transfection
D000954:Antigens, Surface; D004983:Ethanolamines; D006017:Glycolipids; D015292:Glycoprotein Hormones, alpha Subunit; D017261:Glycosylphosphatidylinositols; D010716:Phosphatidylinositols; D011993:Recombinant Fusion Proteins; D018800:Thy-1 Antigens; D019856:Ethanolamine