Distinctive roles of endoplasmic reticulum and golgi glycosylation in functional surface expression of mammalian E-NTPDase1, CD39.
CD39 is a membrane-bound ecto-nucleoside triphosphate diphosphohydrolase that is involved in the regulation of purinergic signaling. It has been previously reported that N-linked glycosylation is essential for the surface localization of CD39 and for its cellular activity. Here we have addressed the roles of different stages of N-linked glycosylation on CD39's activity and surface expression by using various glycosylation inhibitors, glycosylation deficient CHO cells, and oligosaccharide removal enzymes. The results demonstrate that endoplasmic reticulum glycosylation is required for protein folding and essential for functional surface expression of CD39, while Golgi glycosylation is less important. The study has also shown that N-linked glycosylation of CD39 is dispensable for the activity after the protein is properly folded and targeted.
Zhong
Xiaotian
X
Department of Chemical and Screening Sciences, Wyeth Research, 85 Bolton Street, Cambridge, MA 02140, United States. xzhong@wyeth.com
Kriz
Ron
R
Kumar
Ravindra
R
Guidotti
Guido
G
D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000818:Animals; D015703:Antigens, CD / Q000378:metabolism*; D001081:Apyrase; D016466:CHO Cells; D019556:COS Cells; D006224:Cricetinae; D004721:Endoplasmic Reticulum / Q000502:physiology*; D006026:Glycoside Hydrolases / Q000494:pharmacology; D006031:Glycosylation; D006056:Golgi Apparatus / Q000378:metabolism*; D043524:Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase / Q000494:pharmacology
D015703:Antigens, CD; D006026:Glycoside Hydrolases; D043524:Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase; D000251:Adenosine Triphosphatases; D001081:Apyrase; C067869:CD39 antigen