Lysophosphatidylcholine metabolism to 1,2-diacylglycerol in lymphoblasts: involvement of a phosphatidylcholine-hydrolyzing phospholipase C.
We have previously described the chemoattraction of lymphoblasts by lysophosphatidylcholine [Hoffman, R. D., et al. (1982) Proc. Natl. Acad. Sci. U.S.A. 79, 3285-3289]. In studying the mechanism of chemoattraction it was found that lysophosphatidylcholine was metabolized to 1,2-diacylglycerol by the lymphoblastic cell line 6C3HED. One route of metabolism involves the acylation of lysophosphatidylcholine to phosphatidylcholine with subsequent hydrolysis to 1,2-diacylglycerol and phosphocholine by the action of phospholipase C. The increase in cellular 1,2-diacylglycerol was established by metabolic experiments using [14C]glycerol-labeled lysophosphatidylcholine and by mass measurements of 1,2-diacylglycerol. The presence of a phosphatidylcholine-hydrolyzing phospholipase C was confirmed in 6C3HED cell homogenates. In intact cells, lysophosphatidylcholine induced a pattern of protein phosphorylation similar to those of 1,2-dioctanoylglycerol and phorbol 12-myristate 13-acetate, two known activators of protein kinase C. This pathway of lysophosphatidylcholine metabolism, which involves a phosphatidylcholine-hydrolyzing phospholipase C, may be important in the activation of protein kinase C independent of inositol phospholipid hydrolysis.
Nishijima
J
J
Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205.
Wright
T M
TM
Hoffman
R D
RD
Liao
F
F
Symer
D E
DE
Shin
H S
HS
D000818:Animals; D002460:Cell Line; D004075:Diglycerides / Q000378:metabolism*; D005989:Glycerides / Q000378:metabolism*; D006868:Hydrolysis; D007700:Kinetics; D008223:Lymphoma / Q000201:enzymology; D008244:Lysophosphatidylcholines / Q000378:metabolism*; D051379:Mice; D010713:Phosphatidylcholines / Q000378:metabolism*; D010750:Phosphoproteins / Q000096:biosynthesis / Q000302:isolation & purification; D010766:Phosphorylation; D013953:Thymus Neoplasms / Q000201:enzymology; D010738:Type C Phospholipases / Q000378:metabolism*
D004075:Diglycerides; D005989:Glycerides; D008244:Lysophosphatidylcholines; D010713:Phosphatidylcholines; D010750:Phosphoproteins; D010738:Type C Phospholipases