Synthesis and uptake of gangliosides by choleragen-responsive human fibroblasts.
Synthesis and uptake of gangliosides by choleragen-responsive human fibroblasts.
复制标题
胆原反应性人成纤维细胞合成和摄取神经节苷脂。
DOI：
10.1021/bi00628a017
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发表时间：
1977
期刊：
影响因子：
2.9
通讯作者：
V. Manganiello
中科院分区：
文献类型：
--
作者：
P. Fishman;J. Moss;V. Manganiello
人成纤维细胞，培养在培养基中含有10%的胎牛血清，显着地回应choleragen增加环磷酸腺苷含量大于48倍的基础水平。对这些细胞的神经节苷脂分析表明，主要的神经节苷脂是N-乙酰神经氨酰半乳糖基葡萄糖神经酰胺（GM 3），含有痕量（小于或等于100 pmol/mg蛋白质）的其他神经节苷脂，包括GM 1，推定的促胆固醇受体。虽然细胞含有三个糖基转移酶所需的神经节苷脂的合成，N-乙酰氨基半乳糖转移酶的活性所需的GM 3更复杂的神经节苷脂的转换没有检测到。然而，当细胞在含有[14 C]半乳糖或N-乙酰[3 H]甘露糖胺的培养基中生长时，所有的神经节苷脂都被标记，表明细胞可以合成复杂的神经节苷脂。尽管胎牛血清含有神经节苷脂（包括GM 1），但[3 H] GM 1从生长培养基中摄取较差，并且以观察到的速率摄取可能占细胞GM 1含量的2%以下。当细胞在含有[3 H] GM 1的化学成分确定的培养基中孵育时，神经节苷脂的快速摄取发生，并且细胞的总GM 1含量在不到3小时内增加了3倍。因此，尽管细胞能够结合外源性神经节苷脂，但胎牛血清中的神经节苷脂是细胞不易获得的形式。
Human fibroblasts, cultured in medium containing 10% fetal calf serum, responded dramatically to choleragen with an increase in cyclic adenosine monophosphate content to greater than 48 times basal levels. Analysis of these cells for gangliosides indicated that the major ganglioside was N-acetylneuraminylgalactosylglucosylceramide (GM3) with trace amounts (less than or equal to 100 pmol/mg of protein) of other gangliosides including GM1, the putative choleragen receptor. Although the cells contained three glycosyltransferases required for ganglioside synthesis, the N-acetylgalactosaminyltransferase activity necessary for the conversion of GM3 to more complex gangliosides was not detected. When the cells were grown in medium containing [14C]galactose or N-acety[3H]mannosamine, however, all of the gangliosides became labeled, indicating that the cells can synthesize complex gangliosides. Although fetal calf serum contains gangliosides including GM1, [3H]GM1 was taken up poorly from the growth medium and uptake at the rate observed could have accounted for less than 2% of the GM1 content of the cells. When the cells were incubated in chemically defined medium containing [3H]GM1 at the concentrations present in fetal calf serum, rapid uptake of the ganglioside occurred and the total GM1 content of the cells increased threefold in less than 3 h. Thus, although the cells are capable of binding exogenous gangliosides, the gangliosides in fetal calf serum are in a form not readily available to the cells.