Role of dihydroxyacetonephosphate acyltransferase in the biosynthesis of plasmalogens and nonether glycerolipids.
The variant CHO-K1 cell line, NRel-4, is unable to synthesize plasmalogens because of a severe reduction in dihydroxyacetonephosphate acyltransferase (DHAPAT) activity (Nagan, N., A. K. Hajra, L. K. Larkins, P. Lazarow, P. E. Purdue, W. B. Rizzo, and R. A. Zoeller. 1998. Isolation of a Chinese hamster fibroblast variant defective in dihydroxyacetonephosphate acyltransferase activity and plasmalogen biosynthesis: use of a novel two-step selection protocol. Biochem. J. 332: 273-279). Northern analysis demonstrated that the loss of this activity was attributable to a severe reduction in mRNA levels for DHAPAT. Transfection of NRel-4 cells with a plasmid bearing the human DHAPAT cDNA recovered DHAPAT activity and plasmalogen biosynthesis. Examination of clonal isolates from the transfected population showed that recovery of as little as 10% of wild-type DHAPAT activity restored plasmalogen levels to 55% of normal, whereas in one isolate, NRel-4.15, which overexpressed DHAPAT activity by 6-fold over wild-type cells, plasmalogen levels were returned only to wild-type values. Although the rate of plasmenylethanolamine biosynthesis was restored in NRel-4.15, the biosynthesis of nonether glycerolipids was either decreased or unaffected, suggesting that peroxisomal DHAPAT does not normally contribute to nonether glycerolipid biosynthesis. These data demonstrate that a defect in the gene that codes for peroxisomal DHAPAT is the primary lesion in the NRel-4 cell line and that the peroxisomal DHAPAT is essential for the biosynthesis of plasmalogens in animal cells.
Liu
Dailan
D
Department of Physiology and Biophysics, Boston University School of Medicine, Boston, MA 02118, USA.
Nagan
Narasimhan
N
Just
Wilhelm W
WW
Rodemer
Claus
C
Thai
Thanh-Phuong
TP
Zoeller
Raphael A
RA
D000217:Acyltransferases / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D016466:CHO Cells; D006224:Cricetinae; D019856:Ethanolamine / Q000145:classification / Q000378:metabolism; D020404:Glycerophospholipids / Q000096:biosynthesis* / Q000737:chemistry*; D006801:Humans; D010955:Plasmalogens / Q000096:biosynthesis* / Q000737:chemistry; D010958:Plasminogen / Q000172:deficiency / Q000235:genetics / Q000378:metabolism; D014162:Transfection
D020404:Glycerophospholipids; D010955:Plasmalogens; D019856:Ethanolamine; D010958:Plasminogen; D000217:Acyltransferases; C020051:glycerone-phosphate O-acyltransferase