Publication Date:
1987-10-02
Description:
A group of proteins anchored to the cell by phosphatidylinositol (PI) has recently been identified. The significance of this new class of membrane anchor is unknown; one possibility is that it facilitates release of the molecule by phospholipases. In fact, phospholipase C enzymes specific for the complex carboxyl-terminal glycolipids of these proteins have been isolated from African trypanosomes and from hepatocyte plasma membranes. This study reports the discovery of a glycan-PI-specific phospholipase D in human serum that cleaves both the membrane form of the variant surface glycoprotein of African trypanosomes and its glycolipid precursor, but not phosphatidylethanolamine, phosphatidylcholine, or phosphatidylinositol. Decay-accelerating factor, another PI-anchored molecule, is also cleaved by the enzyme and converted from a hydrophobic to a soluble protein. The enzyme is Ca2+-dependent, heat labile, and not affected by the inhibitor of serine proteases, phenylmethylsulfonylfluoride. Its function is not known, but the present findings indicate that it participates in the metabolism of glycolipid-anchored membrane proteins.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Davitz, M A -- Hereld, D -- Shak, S -- Krakow, J -- Englund, P T -- Nussenzweig, V -- 1-ES00136/ES/NIEHS NIH HHS/ -- GM7309/GM/NIGMS NIH HHS/ -- HL-00650/HL/NHLBI NIH HHS/ -- etc. -- New York, N.Y. -- Science. 1987 Oct 2;238(4823):81-4.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Pathology, New York University School of Medicine, NY 10016.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2443973" target="_blank"〉PubMed〈/a〉
Keywords:
Antigens, CD55
;
Glycolipids/*metabolism
;
Humans
;
Membrane Proteins/metabolism
;
Phosphatidylinositols/*metabolism
;
Phospholipase D/antagonists & inhibitors/*blood
;
Phospholipases/*blood
;
Solubility
;
Substrate Specificity
;
Variant Surface Glycoproteins, Trypanosoma/metabolism
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
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