Transmembrane domain of CD44 is required for its detergent insolubility in fibroblasts.
Transmembrane domain of CD44 is required for its detergent insolubility in fibroblasts.
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发表时间：
1995-03
影响因子：
4
通讯作者：
Astrid Perschl;J. Lesley;N. English;R. Hyman;Ian S. Trowbridge
中科院分区：
文献类型：
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作者：
Astrid Perschl;J. Lesley;N. English;R. Hyman;Ian S. Trowbridge
透明质酸受体CD44是一种丰富的糖蛋白，在多种不同的细胞类型中表达。在成纤维细胞中，经过Triton X-100萃取后，很大一部分受体分子仍留在洗涤剂不溶部分。这些CD44分子的洗涤剂不溶性被解释为反映了它们与细胞骨架的关联。在这项研究中，我们研究了CD44在小鼠成纤维细胞中Triton X-100不溶性所需的结构特征。我们在L细胞中表达了野生型造血形式的CD44，一个缺乏细胞质结构域的突变CD44，以及两个具有取代跨膜结构域的突变CD44分子。免疫荧光和细胞表面碘化，并测定转染CD44分子的洗涤剂提取谱。在野生型和无尾突变体转染的分子之间，洗涤剂溶解度没有差异。然而，两种具有异源跨膜结构域的CD44突变体（来自CD3 zeta链或CD45）在Triton X-100中完全可溶。这些结果表明，CD44的跨膜区域而不是细胞质区域是这些细胞中洗涤剂不溶性所必需的。在细胞松弛素D处理前后，CD44和肌动蛋白应激纤维没有明显的共定位，野生型和突变型CD44分子的洗涤剂提取谱也没有受到细胞松弛素D的影响。在平衡密度蔗糖梯度中，在低密度部分发现了Triton不溶性CD44成分，表明其与Triton x -100不溶性脂质有关。（摘要删节250字）
The hyaluronan receptor CD44 is an abundant glycoprotein expressed on a variety of different cell types. In fibroblasts a significant portion of receptor molecules remain in the detergent-insoluble fraction after Triton X-100 extraction. Detergent insolubility of these CD44 molecules has been interpreted to reflect their association with the cytoskeleton. In this study we examined the structural features of CD44 required for its Triton X-100 insolubility in murine fibroblasts. We expressed in L cells the wild-type hematopoietic form of CD44, a mutant CD44 lacking the cytoplasmic domain, and two mutant CD44 molecules with substituted transmembrane domains. Immunofluorescence and cell surface iodination were performed and the detergent extraction profile of the transfected CD44 molecules was determined. No difference in detergent solubility was observed between wild-type and tailless mutant-transfected molecules. However, both CD44 mutants with a heterologous transmembrane domain, derived from either the CD3 zeta chain or CD45, were completely soluble in Triton X-100. These results demonstrate that the transmembrane region but not the cytoplasmic domain of CD44 is required for the detergent-insolubility in these cells. No obvious colocalization of CD44 and actin stress fibers was observed before or after treatment with cytochalasin D, and no change in the detergent extraction profile of wild-type and mutant CD44 molecules was effected by cytochalasin D. In equilibrium density sucrose gradients the Triton-insoluble CD44 component was found in the low density fractions, indicating an association with Triton X-100-insoluble lipids.(ABSTRACT TRUNCATED AT 250 WORDS)