Iida H, Shibata Y
Department of Anatomy, Faculty of Medicine, Kyushu University, Fukuoka, Japan.
J Histochem Cytochem. 1989 Dec;37(12):1885-92. doi: 10.1177/37.12.2479675.
To examine whether and how internalized plasma membrane components are routed to the compartment of the biosynthetic-exocytic pathway in cultured atrial myocytes, the plasma membrane labeled with wheat germ agglutinin conjugated to horseradish peroxidase (WGA-HRP) was traced electron microscopically by cytochemical detection of HRP. The WGA-HRP label was internalized via a coated pit-small vesicle pathway and reached vacuoles and endosomes by 3 min. Labeled endosomes comprised vacuoles and tubular elements containing reaction product. By 15 min, similar tubular structures containing reaction product accumulated in the area of the trans-Golgi network (TGN). The labeled TGN consisted of interconnected tubular elements, which often connected to atrial granules containing reaction product. In contrast, neither native HRP nor Lucifer Yellow reached Golgi elements or atrial granules. These results suggest that a proportion of the plasma membrane labeled with WGA-HRP is delivered to endosomes, from which tubules might bud off to transfer the tracer molecules to the TGN, where the lectin conjugate and associated membranes are packaged into atrial granules.
为了研究内化的质膜成分是否以及如何被转运到培养心房肌细胞生物合成-分泌途径的区室中，通过辣根过氧化物酶（HRP）的细胞化学检测，在电子显微镜下追踪用与辣根过氧化物酶偶联的麦胚凝集素（WGA-HRP）标记的质膜。WGA-HRP标记物通过有被小窝-小泡途径内化，3分钟时到达液泡和内体。标记的内体包括含有反应产物的液泡和管状结构。15分钟时，含有反应产物的类似管状结构在反式高尔基体网络（TGN）区域积累。标记的TGN由相互连接的管状结构组成，这些管状结构常常与含有反应产物的心房颗粒相连。相比之下，天然HRP和路西法黄均未到达高尔基体成分或心房颗粒。这些结果表明，一部分用WGA-HRP标记的质膜被转运到内体，小管可能从内体上芽生出来，将示踪分子转运到TGN，在那里凝集素偶联物和相关膜被包装到心房颗粒中。
