Jumblatt J E, Schlup V, Burger M M
Biochemistry. 1980 Mar 4;19(5):1038-42. doi: 10.1021/bi00546a032.
Previous studies have established that the mechanism of species-specific sponge cell reaggregation in vitro involves at least three components: a species-specific aggregation factor, its cell surface receptors, and Ca2+ ions. Here we report about the binding of Microciona 125I-labeled aggregation factor to cells and to other molecules of aggregation factor coupled to agarose beads, as well as the role of divalent cations in both factor-cell and factor-factor interactions. Our results indicate that cell aggregation is a two-step process, involving (1) Ca2+-independent species-specific binding of the 21 X 106 dalton aggregation factor to cellular receptors and (2) formation of Ca2+-dependent linkages between factor molecules on adjacent cells. Quantitation of binding suggests that less than 5% of the cell-associated aggregation factor in vivo is required for cell-cell adhesion in the in vitro assay. Alternative biological functions for the aggregation factor are discussed.
先前的研究已证实，体外物种特异性海绵细胞重新聚集的机制至少涉及三个成分：物种特异性聚集因子、其细胞表面受体和钙离子。在此，我们报告了微小多细胞海绵125I标记的聚集因子与细胞以及与琼脂糖珠偶联的聚集因子的其他分子的结合情况，以及二价阳离子在因子-细胞和因子-因子相互作用中的作用。我们的结果表明，细胞聚集是一个两步过程，包括(1) 21×106道尔顿聚集因子与细胞受体的钙离子非依赖性物种特异性结合，以及(2) 相邻细胞上因子分子之间形成钙离子依赖性连接。结合定量分析表明，体外测定中细胞间黏附所需的体内细胞相关聚集因子不到5%。文中还讨论了聚集因子的其他生物学功能。
