Neutra M R, Wilson J M, Weltzin R A, Kraehenbuhl J P
Department of Anatomy and Cellular Biology, Harvard Medical School, Boston, Massachusetts 02115.
Am Rev Respir Dis. 1988 Dec;138(6 Pt 2):S10-6. doi: 10.1164/ajrccm/138.6_Pt_2.S10.
Epithelial cell plasma membranes are organized as biochemically and functionally distinct domains and subdomains. We have explored the composition and maintenance of specific membrane regions during endocytosis and transepithelial vesicular transport in specialized cells of the intestinal epithelium. A unique membrane glycoprotein has been identified in apical endocytic subdomains and endosomal tubules of absorptive cells in suckling rat ileum. This endocytic system is involved in sorting and transepithelial transport of peptide growth factors as well as delivery of milk macromolecules to lysosomes. In M cells of follicle-associated epithelium, we have shown that membrane-bound proteins are efficiently transported to a specialized subdomain of basolateral membrane. The apical membranes of these cells bear immunoglobulin binding sites and transport monoclonal IgA antibodies to the basolateral side, where they may interact with cells of the mucosal immune system.
上皮细胞质膜被组织成具有生化和功能差异的结构域和亚结构域。我们已经研究了肠道上皮特化细胞在胞吞作用和跨上皮囊泡运输过程中特定膜区域的组成和维持。在乳鼠回肠吸收细胞的顶端胞吞亚结构域和内体小管中鉴定出一种独特的膜糖蛋白。这个胞吞系统参与肽生长因子的分选和跨上皮运输，以及将乳汁大分子递送至溶酶体。在滤泡相关上皮的M细胞中，我们已经证明膜结合蛋白能有效地运输到基底外侧膜的一个特化亚结构域。这些细胞的顶端膜带有免疫球蛋白结合位点，并将单克隆IgA抗体运输到基底外侧，在那里它们可能与黏膜免疫系统的细胞相互作用。
