Cellular mechanisms of the clearance function of type C receptors of atrial natriuretic factor.
Cellular mechanisms of the clearance function of type C receptors of atrial natriuretic factor.
复制标题
DOI：
10.1016/s0021-9258(17)45309-9
复制
发表时间：
1990-12
期刊：
影响因子：
--
通讯作者：
D. Nussenzveig;J. Lewicki;T. Maack
中科院分区：
文献类型：
--
作者：
D. Nussenzveig;J. Lewicki;T. Maack
心房钠尿因子 (ANF) 的清除 (C) 受体在清除循环中的 ANF 方面发挥着重要作用。在本研究中，我们研究了该功能的细胞机制。 125I-ANF1-28 与培养的牛血管平滑肌细胞中的 C-ANF 受体特异性结合，在 37°C 下通过温度依赖性过程以 5% 占据受体/分钟的速率内化。内化的 125I-ANF1-28 快速代谢并以 [125I] 单碘酪氨酸形式释放到培养基中，该过程被 NH4Cl 可逆地抑制 (10毫米）。当通过预先与 NH4Cl 孵育使细胞内配体积累最大化时，可以检测到受体-配体复合物的后吞吞作用。在存在饱和浓度的 125I-ANF1-28 的情况下，当细胞从 4 摄氏度升温至 37 摄氏度时，表面 C-ANF 受体首先减少，然后几乎完全补充，这种现象不会因放线菌酮抑制蛋白质合成而改变。在没有温度转变的情况下，表面C-ANF受体的密度保持恒定，并且通过孵育2小时，水解的ANF量远远超过C-ANF受体的总量。表面 C-ANF 受体的总数每小时都会内化和循环，并且这些过程是组成性的，因为它们也在没有配体的情况下发生。胰蛋白酶化和溶解实验进一步表明C-ANF受体被快速内化并再循环至细胞膜。结果表明，受体-配体内化、广泛的受体再循环和ANF的溶酶体水解是C-ANF受体发挥其清除功能的细胞机制。
Clearance (C) receptors of atrial natriuretic factor (ANF) have an important role of removing ANF from the circulation. In the present study we investigated the cellular mechanisms of this function. 125I-ANF1-28 specifically bound to C-ANF receptors in cultured bovine vascular smooth muscle cells is internalized by a temperature-dependent process at a rate of 5% occupied receptors/min at 37 degrees C. Internalized 125I-ANF1-28 is rapidly metabolized and released to the medium as [125I]monoiodotyrosine, a process that is reversibly inhibited by NH4Cl (10 mM). Retroendocytosis of receptor-ligand complex is detectable when intracellular accumulation of the ligand is maximized by previous incubation with NH4Cl. In the presence of saturating concentrations of 125I-ANF1-28 when cells are warmed from 4 to 37 degrees C, there is first a decrease and then an almost complete replenishment of surface C-ANF receptors, a phenomenon that is not altered by protein synthesis inhibition with cycloheximide. In the absence of temperature transition, the density of surface C-ANF receptors remains constant, and by 2 h of incubation the amount of ANF hydrolyzed far exceeds the total amount of C-ANF receptors. The total population of surface C-ANF receptors is internalized and recycled every hour, and these processes are constitutive since they also occur in the absence of ligand. Trypsinization and solubilization experiments further indicate that C-ANF receptors are rapidly internalized and recycled to the cell membrane. The results demonstrate that receptor-ligand internalization, extensive receptor recycling, and lysosomal hydrolysis of ANF are the cellular mechanisms by which C-ANF receptors exert their clearance function.