THE ROLE OF SPHINGOMYELIN IN PHOSPHATIDYLCHOLINE METABOLISM IN CULTURED HUMAN FIBROBLASTS FROM CONTROL AND SPHINGOMYELIN LIPIDOSIS PATIENTS AND IN CHINESE HAMSTER OVARY CELLS

被引:11
作者
SPENCE, MW
COOK, HW
BYERS, DM
PALMER, FBS
机构
[1] DALHOUSIE UNIV,DEPT PEDIAT,HALIFAX B3H 4H7,NS,CANADA
[2] DALHOUSIE UNIV,DEPT BIOCHEM,HALIFAX B3H 4H7,NS,CANADA
关键词
y;
D O I
10.1042/bj2680719
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
Human fibroblasts in culture take up exogenous [choline-Me-3H, 32P]sphingomyelin (SM) from the medium and incorporate it into cellular SM and phosphatidylcholine [Spence, Clarke and Cook (1983) J. Biol. Chem. 258, 8595-8600]. The ratio of [3H]choline/[32P]P(i) is similar in SM and phosphatidylcholine, indicating that the phosphocholine (P-Cho) moiety is transferred intact. Similar results are obtained with Niemann-Pick (NP) cells which are deficient in lysosomal sphingomyelinase activity, suggesting that the P-Cho transfer may not be mediated by the lysosomal sphingomyelinase and that alternative pathways of sphingomyelin catabolism are present in cultured cells. In this study we have shown that: (1) the P-Cho pool in control and NP cells incubated with exogenous labelled SM has a specific radioactivity intermediate between that of SM and PtdCho; (2) expansion of the intracellular P-Cho pool by incubation with exogenous choline reduces the incorporation of [3H]choline from SM into PtdCho; and (3) incorporation of P-Cho from SM into PtdCho is decreased at the non-permissive temperature in Chinese hamster ovary cells with a temperature-sensitive mutation in the cytidylyltransferase reaction. These results suggest that incorporation of P-Cho from SM into PtdCho involves a reaction sequence in which P-Cho is hydrolysed from SM by a sphingomyelinase, followed by incorporation of P-Cho into PtdCho via the cytidine pathway of biosynthesis (SM → P-Cho → CDP-Cho → PtdCho). The appreciable incorporation of P-Cho from SM into PtdCho in sphingomyelinase-deficient NP cells suggests a more substantial or effective lysosomal sphingomyelinase activity in intact cells than is measured in vitro, and/or a significant contribution by other sphingomyelinase activities in these cells.
引用
收藏
页码:719 / 724
页数:6
相关论文
共 30 条
[1]   PHOSPHATIDYLCHOLINE AS A SOURCE OF DIACYLGLYCEROLS IN NEURONAL NUCLEI INCUBATED IN THE PRESENCE OF EGTA AND CMP [J].
BAKER, RR ;
CHANG, HY .
BIOCHIMICA ET BIOPHYSICA ACTA, 1984, 796 (01) :55-63
[2]  
BARENHOLZ Y, 1966, J BIOL CHEM, V241, P3731
[3]   METABOLISM OF SPHINGOMYELIN BY INTACT CULTURED FIBROBLASTS - DIFFERENTIATION OF NIEMANN-PICK DISEASE TYPE-A AND TYPE-B [J].
BEAUDET, AL ;
MANSCHRECK, AA .
BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS, 1982, 105 (01) :14-19
[4]  
BOCCKINO SB, 1985, J BIOL CHEM, V260, P4201
[5]   THE PHOSPHATIDYLCHOLINE PATHWAY OF DIACYLGLYCEROL FORMATION STIMULATED BY PHORBOL DIESTERS OCCURS VIA PHOSPHOLIPASE-D ACTIVATION [J].
CABOT, MC ;
WELSH, CJ ;
CAO, HT ;
CHABBOTT, H .
FEBS LETTERS, 1988, 233 (01) :153-157
[6]   ISOLATION OF PLASMA-MEMBRANES FROM CULTURED GLIOMA-CELLS AND APPLICATION TO EVALUATION OF MEMBRANE SPHINGOMYELIN TURNOVER [J].
COOK, HW ;
PALMER, FBS ;
BYERS, DM ;
SPENCE, MW .
ANALYTICAL BIOCHEMISTRY, 1988, 174 (02) :552-560
[7]   AUTORADIOGRAPHIC DETECTION OF ANIMAL-CELL MEMBRANE MUTANTS ALTERED IN PHOSPHATIDYLCHOLINE SYNTHESIS [J].
ESKO, JD ;
RAETZ, CRH .
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA-BIOLOGICAL SCIENCES, 1980, 77 (09) :5192-5196
[8]  
ESKO JD, 1981, J BIOL CHEM, V256, P7388
[9]  
FOLCH J, 1957, J BIOL CHEM, V226, P497
[10]  
FREDRICKSON DS, 1972, METABOLIC BASIS INHE, P783