細(xì)胞膜和細(xì)胞表面ppt課件-資料下載頁
2025-05-04 12:01本頁面
【正文】 d by Cadherins E鈣黏素介導(dǎo)的中間連接。鈣黏素的細(xì)胞部分通過接頭蛋白和肌動蛋白纖維相連。 橋粒鈣黏素， Desmosomal Cadherins ? 細(xì)胞部分的接頭蛋白形成斑塊狀，通過其與中間纖維相連 ? contain two specialized cadherin proteins, desmoglein and desmocollin, whose cytosolic domains are distinct from those in the classical cadherins. The cytosolic domains of desmosomal cadherins interact with plakoglobin and the plakophilins. These adapter proteins, which form the thick cytoplasmic plaques characteristic of desmosomes, in turn interact with intermediate filaments. 緊密連接封閉細(xì)胞間縫隙，限制膜流動 Tight Junctions Seal Off Body Cavities and Restrict Diffusion of Membrane Components ? 緊密連接形成屏障，將細(xì)胞兩側(cè)液體分開 ? For polarized epithelial cells to carry out their functions as barriers and mediators of selective transport, extracellular fluids surrounding their apical and basolateral membranes must be kept separate. 緊密連接中的 2種主要蛋白 occludin and claudin. The two principal integralmembrane proteins found in tight junctions are occludin and claudin. 另外一種分子 JAMs，屬于免疫球蛋白超家族 Recently, a group of junction adhesion molecules (JAMs) have been found to contribute to homophilic adhesion and other functions of tight junctions. 細(xì)胞間的通路，縫隙連接 Passageways from cell to cell:gap junctions ? 由六個 connexin構(gòu)成連接子， 中間有。 ,相鄰膜連接子對接形成跨膜通道。 ? Gap Junctions Composed of Connexins Allow Small Molecules to Pass Between Adjacent Cells 選擇素，在血液中介導(dǎo)細(xì)胞間粘著 selectin mediate transient cellcell adhesions in the bloodstream ? 屬異親性依賴于 Ca2+的能與特異糖基識別并相結(jié)合的糖蛋白，其胞外部分具有凝集素樣結(jié)構(gòu)域 (lectinlike domain)。主要參與白細(xì)胞與血管（淋巴管）內(nèi)皮細(xì)胞之間的識別與粘著。 ? Selecins are cellsurface carbohydratebingding proteins that mediate a variety of transient, cellcell adhesins interactions in the bloodstream. ? 白細(xì)胞表面有 L選擇素，血小板和炎癥激活內(nèi)皮細(xì)胞表達(dá) P選擇素，激活內(nèi)皮細(xì)胞表達(dá) E選擇素。 ? There are at least three types: Lselectin on white blood cells, Pselectin on blood platelets and on endothelial cells that have been locally activated by an inflammatory response, and Eselectin on activated endothelial cells. 免疫球蛋白超家族的 CAM(IgSuperfamily， IgSF) ? 分子結(jié)構(gòu)中具有與免疫球蛋白類似的結(jié)構(gòu)域的 CAM超家族。介導(dǎo)同親性細(xì)胞粘著或介導(dǎo)異親性細(xì)胞粘著 ,但其粘著作用不依賴 Ca2+，其中 NCAMs 在神經(jīng)組織細(xì)胞間的粘著中起主要作用。 整合素 Many Cell–Matrix and Some Cell–Cell Interactions Are Mediated by Integrins ? 由 α和 β兩個亞基形成的異源二聚體糖蛋白?？膳c不同的配基結(jié)合，從而介導(dǎo)細(xì)胞與基質(zhì)、細(xì)胞與細(xì)胞之間的粘著。 問題 ? 如何理解細(xì)胞膜流動鑲嵌模型 ? 膜脂的構(gòu)成與膜的不對稱性 ? 細(xì)胞的緊密連接，中間連接，橋粒，縫隙連接與連接分子關(guān)系。 ? 從白細(xì)胞出血管，理解細(xì)胞粘連分子在其中的作用。
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