Barazzone P, Carpentier J L, Gorden P, Van Obberghen E, Orci L
Nature. 1980 Jul 24;286(5771):401-3. doi: 10.1038/286401a0.
Cultured human lymphocytes of the IM-9 line have specific binding sites for 125I-insulin that have been characterized in detail. When the hormone--cell interaction was studied by quantitative electron microscopic (EM) autoradiography, it was shown that initial binding was to the plasma membrane and that at 37 degrees C a small fraction of the ligand was internalized by the cell. The internalized ligand was found preferentially localized in lysosomes in the Golgi region of the cell. It is well known that di- or multivalent ligands redistribute in the plane of the membrane before internalization. We now report that following initial binding the univalent ligand insulin also undergoes a polar redistribution ('capping') before internalization.
IM-9系培养的人淋巴细胞具有已被详细表征的125I-胰岛素特异性结合位点。当通过定量电子显微镜（EM）放射自显影研究激素与细胞的相互作用时，结果表明初始结合发生在质膜上，并且在37℃时一小部分配体被细胞内化。内化的配体优先定位于细胞高尔基体区域的溶酶体中。众所周知，二价或多价配体在内化之前会在膜平面内重新分布。我们现在报告，在初始结合后，单价配体胰岛素在内化之前也会发生极性重新分布（“帽化”）。
