Receptor-mediated endocytosis of alpha 2-macroglobulin by principal cells in the proximal caput epididymidis in vivo.
Receptor-mediated endocytosis of alpha 2-macroglobulin by principal cells in the proximal caput epididymidis in vivo.
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体内近端附睾主细胞对α2-巨球蛋白的受体介导的内吞作用。
DOI：
10.1002/j.1939-4640.1985.tb00835.x
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发表时间：
1985
影响因子：
--
通讯作者：
Dym,M
中科院分区：
文献类型：
--
作者：
Djakiew,D;Byers,SW;Lewis,DM;Dym,M
使用微穿刺技术研究对照大鼠和传出管结扎大鼠近端附睾中主细胞对与胶体金（α2M-金）结合的α2-巨球蛋白的受体介导的内吞作用。体内受体介导的α2-巨球蛋白-金内吞作用的途径与体外发生的相似。 α2-巨球蛋白-金被包被的小凹和包被的囊泡吸收和内化，并依次定位于未包被的囊泡（内体）、管状囊泡结构、多囊泡体和溶酶体中。然而，100 倍过量的 α2-巨球蛋白并没有取代对照大鼠主细胞对 α2-巨球蛋白-金的摄取。相比之下，传出管结扎大鼠的主细胞对 α2-巨球蛋白-金的摄取比对照大鼠高六倍，并且可以通过 100 倍过量的 α2-巨球蛋白替代至对照水平。这表明，对照大鼠中 100 倍过量的 α2-巨球蛋白无法取代 α2-巨球蛋白-金的摄取，是由于主细胞上表观 α2-巨球蛋白受体的正常饱和。传出管结扎的作用是去除高水平的内源性α2-巨球蛋白，从而耗尽α2-巨球蛋白受体，从而允许传出管结扎大鼠更高地摄取α2-巨球蛋白-金。
Micropuncture techniques were used to study receptor‐mediated endocytosis of α2‐macroglobulin bound to colloidal gold (α2M‐gold) by principal cells in the proximal caput epididymidis of control and efferent duct‐ligated rats. The pathway of receptor‐mediated endocytosis of α2‐macroglobulin‐goldin vivowas similar to that which occursin vitro. Alpha2‐macroglobulin‐gold was taken up and internalized in coated pits and coated vesicles and was localized sequentially in uncoated vesicles (endosomes), tubular‐vesicular structures, multivesicular bodies, and lysosomes. However, a 100‐fold excess of α2‐macroglobulin did not displace the uptake of α2‐macroglobulin‐gold in principal cells from control rats. In contrast, uptake of α2‐macroglobulin‐gold by principal cells from efferent duct‐ligated rats was six‐fold greater than in control rats, and could be displaced to control levels by a 100‐fold excess of α2‐macroglobulin. It is suggested that the inability of a 100‐fold excess of α2‐macroglobulin to displace uptake of α2‐macroglobulin‐gold in control rats was due to the normal saturation of apparent α2‐macroglobulin receptors on principal cells. The effect of efferent duct ligation was to remove the high levels of endogenous α2‐macroglobulin, which depleted the receptors of α2‐macroglobulin, thereby allowing a higher uptake of α2‐macroglobulin‐gold in the efferent duct‐ligated rats.