Affected paroxysmal nocturnal hemoglobinuria T lymphocytes harbor a common defect in assembly of N-acetyl-D-glucosamine inositol phospholipid corresponding to that in class A Thy-1- murine lymphoma mutants.

Abstract

Deficient expression of glycoinositol phospholipid (GPI) anchored proteins in affected paroxysmal nocturnal hemoglobinuria (PNH) cells has been traced to a defect in GPI anchor assembly. In a previous study (Schubert, J., Schmidt, R. E., and Medof, M. E. (1993) J. Biol. Chem., in press) we characterized the biosynthesis of putative Man-containing GPI anchor precursors in normal peripheral blood lymphocytes and investigated assembly of these intracellular GPI intermediates in CD48- affected and CD48+ unaffected T and natural killer cell lines of PNH patients. We found that affected T cells from five patients exhibited a uniform defect in which dolichol-phosphoryl-Man was synthesized but no GPI mannolipids were expressed. In this study, membranes of patients' affected T cells were labeled with UDP-[3H]GlcNAc to evaluate earlier steps in GPI synthesis, and intact cells were fused to Thy-1- murine lymphoma mutants harboring different defects in early GPI assembly to test for the presence of corresponding or complementary lesions. In all cases, affected cell membranes failed to assemble GlcNAc-inositol phospholipid, the initial precursor of GPI anchor structures, and the intact cells failed to complement class A mutants while complementing other classes. Affected polymorphonuclear leukocytes from three additional patients of different origin were then labeled with [3H]Man and the labeling patterns found to correspond to those obtained with the T lymphocytes. Taken together the data indicate that the genetic lesion in PNH cells resides in a DNA element which: 1) encodes a product required for the synthesis of GlcNAc-inositol phospholipid, 2) corresponds to that altered in class A Thy-1- murine lymphoma mutants, and 3) is commonly affected in different patients.

• Authors: C Armstrong, J Schubert, E Ueda, J J Knez, D Gelperin, S Hirose, R Silber, S Hollan, R E Schmidt, M E Medof
• Journal: The Journal of biological chemistry (J Biol Chem) Vol. 267 Issue 35 Pg. 25347-51 (Dec 15 1992) ISSN: 0021-9258 [Print] United States
• PMID: 1460030 (Publication Type: Comparative Study, Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Antigens, CD
• CD48 Antigen
• CD48 protein, human
• Cd48 protein, mouse
• Glycosylphosphatidylinositols
• Uridine Diphosphate N-Acetylglucosamine
• Dolichol Monophosphate Mannose
• Mannose
• Acetylglucosamine

Topics

• Acetylglucosamine (metabolism)
• Animals
• Antigens, CD (genetics)
• CD48 Antigen
• Cell Membrane (metabolism)
• Dolichol Monophosphate Mannose (metabolism)
• Glycosylphosphatidylinositols (metabolism)
• Hemoglobinuria, Paroxysmal (genetics, immunology, metabolism)
• Humans
• Killer Cells, Natural (immunology)
• Lymphoma (genetics, immunology, metabolism)
• Mannose (blood)
• Mice
• Mutation
• Neutrophils (immunology, metabolism)
• Trypanosoma brucei brucei (metabolism)
• Uridine Diphosphate N-Acetylglucosamine (metabolism)