SECRETION OF THE BABY HAMSTER-KIDNEY 30-KDA GALACTOSE-BINDING LECTIN FROM POLARIZED AND NONPOLARIZED CELLS - A PATHWAY INDEPENDENT OF THE ENDOPLASMIC RETICULUM-GOLGI COMPLEX
SECRETION OF THE BABY HAMSTER-KIDNEY 30-KDA GALACTOSE-BINDING LECTIN FROM POLARIZED AND NONPOLARIZED CELLS - A PATHWAY INDEPENDENT OF THE ENDOPLASMIC RETICULUM-GOLGI COMPLEX
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DOI：
10.1006/excr.1993.1157
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发表时间：
1993-07-01
影响因子：
3.7
通讯作者：
HUGHES, RC
中科院分区：
文献类型：
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作者：
SATO, S;BURDETT, I;HUGHES, RC
从幼仓鼠肾 (BHK) 细胞中分离出的分子量为 30 kDa 的碳水化合物结合蛋白 (CBP30) 可结合显着存在于癌胚来源的细胞外基质糖蛋白上的聚乳糖胺聚糖，例如 Engelbroth-Holm-Swarm (EHS) 肿瘤层粘连蛋白和羊水纤连蛋白，并抑制 BHK 细胞与整合素介导的 EHS 层粘连蛋白基质的附着和扩散表明凝集素具有细胞外功能（S. Sato 和 R. C. Hughes (1992)J. Biol. Chem.267, (6983-6990)。在这里，我们表明 CBP30 与其他大小相似的凝集素（例如鼠 CBP35、Mac2 抗原和大鼠 IgE 结合蛋白）具有氨基酸序列同源性。与大多数分泌蛋白不同，这些凝集素不包含信号序列，并且我们报告说，抑制经典分泌（糖）蛋白的细胞内转运的药物（例如布雷菲德菌素 A 和莫能菌素）不会阻止 BHK 细胞分泌 CBP30。甲胺和血清饥饿会抑制分泌，并且热休克和钙离子载体 A23187 会增加分泌，而已知的治疗方法分别会阻止或刺激胞吐作用。 BHK 细胞的半衰期约为 30 小时，并且在汇合时也有少量沉积在细胞表面和基质上，CBP30 组装成斑块，最终出现在质膜下方，并且细胞外沉积物变得更多。基底域并融入细胞和基质之间的基质中。
A carbohydrate-binding protein of molecular weight 30 kDa (CBP30) isolated from baby hamster kidney (BHK) cells binds polylactosamine glycans present prominently on extracellular matrix glycoproteins of oncofetal origin, such as Engelbroth-Holm-Swarm (EHS) tumor laminin and amniotic fluid fibronectin, and inhibits attachment and spreading of BHK cells to EHS laminin substrata mediated by integrin(s) suggesting an extracellular function for the lectin (S. Sato and R. C. Hughes (1992)J. Biol. Chem.267, (6983-6990). Here we show that CBP30 shares amino acid sequence homologies with other lectins of similar size, e.g., murine CBP35, Mac2 antigens, and rat IgE-binding protein. Unlike most secreted proteins these lectins contain no signal sequence and we report that drugs, such as brefeldin A and monensin, which inhibit the intracellular transport of classical secretory (glyco)proteins do not block secretion of CBP30 from BHK cells. Secretion is inhibited by methylamine and serum starvation and is increased by heat shock and calcium ionophore A23187, treatments known to block or stimulate exocytosis, respectively. Immunofluorescence and biochemical analysis shows that CBP30 is distributed throughout the cytoplasm of subconfluent BHK cells where it turns over with a half-life of about 30 h, and small amounts are also deposited on the cell surface and substratum. At confluency, the CBP30 assembles into patches that eventually appear to underlie the plasma membrane and extracellular deposits become more numerous. In filter-grown confluent monolayers of Madin-Darby canine kidney cells the lectin is secreted from and expressed at the apical domain of the polarized cells whereas laminin is secreted from the basal domain and becomes incorporated into the matrix between cells and substratum.