De Luca L M, Sasak W, Adamo S, Bhat P V, Akalovsky I, Silverman-Jones C S, Maestri N
Environ Health Perspect. 1980 Apr;35:147-52. doi: 10.1289/ehp.8035147.
Vitamin A and its derivaties (retinoids) are necessary for the maintenance of normal phenotypic expression. An attempt at understanding the biochemical role of vitamin A had led to the demonstration of a new pathway for retinol. In this pathway, vitamin A is phosphorylated to retinylphosphate (RP), which is then glycosylated to retinylphosphatemannose (MRP). These two derivatives have been found in a variety of tissues in vivo and in vitro and appear to be ubiquitous components of cellular membranes. The suggestion has been made that MRP may mediate specific cellular interactions by functioning as a lipid intermediate in the biosynthesis of specific glycoconjugates. A study on spontaneously-transformed mouse fibroblasts (Balb/c 3T12-3 cells) has shown that retinoids are active in increasing the adhesive properties of these cells as measured in an EDTA-mediated detachment assay. Various retinoids were tested for their activity in the adhesion test, and this activity was found to correlate well with their biological activity in maintaining the expression of normal epithelial differentiation in other systems. Retinoic acid, 5,6-epoxyretinol, and 5,6-epoxyretinoic acid were the most active compounds. Retinoids without biological activity in other systems were also inactive in inducihg adhesive properties of 3T12-3 cells. Among these were the synthetic derivatives of retinol, anhydroretinol, and 4,5-monoeneperhydroretinol, and the phenyl derivative of retinoic acid. Beta-Ionone, abscisic acid, and juvenile hormone, which are devoid of vitamin A activity in other systems, were also inactive in this system. Retinoid-induced changes in cell surface proteins were investigated but no difference in 125I-fibronectin (MW 220,000) was detectable between retinoid-treated and untreated cells. However, these cells synthesized retinylphosphatemannose and the incorporation of 2-3H-mannose into a specific glycoprotein (gp 180) was found to be enhanced specifically by retinoid treatment. Investigations of the involvement of gp 180 in adhesion are in progress.
维生素A及其衍生物（类视黄醇）对于维持正常的表型表达是必需的。对理解维生素A生化作用的尝试已导致了视黄醇新途径的证明。在该途径中，维生素A被磷酸化为视黄基磷酸酯（RP），然后被糖基化为视黄基磷酸甘露糖（MRP）。这两种衍生物已在体内和体外的多种组织中被发现，并且似乎是细胞膜中普遍存在的成分。有人提出，MRP可能通过作为特定糖缀合物生物合成中的脂质中间体来介导特定的细胞相互作用。一项对自发转化的小鼠成纤维细胞（Balb/c 3T12 - 3细胞）的研究表明，类视黄醇在增加这些细胞的黏附特性方面具有活性，这是在EDTA介导的脱离试验中测量的。测试了各种类视黄醇在黏附试验中的活性，发现这种活性与其在维持其他系统中正常上皮分化表达的生物活性密切相关。视黄酸、5,6 - 环氧视黄醇和5,6 - 环氧视黄酸是最具活性的化合物。在其他系统中无生物活性的类视黄醇在诱导3T12 - 3细胞的黏附特性方面也无活性。其中包括视黄醇的合成衍生物、脱水视黄醇和4,5 - 单烯全氢视黄醇，以及视黄酸的苯基衍生物。β - 紫罗兰酮、脱落酸和保幼激素在其他系统中缺乏维生素A活性，在该系统中也无活性。研究了类视黄醇诱导细胞表面蛋白的变化，但在类视黄醇处理和未处理的细胞之间未检测到125I - 纤连蛋白（分子量220,000）有差异。然而，这些细胞合成视黄基磷酸甘露糖，并且发现用类视黄醇处理可特异性增强2 - 3H - 甘露糖掺入一种特定糖蛋白（gp 180）。关于gp 180参与黏附的研究正在进行中。
