细胞粘附分子.ppt

2021/3/23 * 2) CA-INDEPENDENT CAMs (Ig-like CAMs) members of the immunoglobulin superfamily involved cell-cell non-junctional adhesions single-pass transmembrane glycoproteins many isoforms, weaker interactions, changes of N-CAM expression in development N-CAMs: mostly homophilic (Neural CAM) I-CAMs: heterophilic (Intercellular CAMs (on activated endothelial cells) the extracellular side: 5 Ig-like repeats and 1-2 fibronectin (type III) repeats various extent of glycosylation the cytoplasmic side: variable, involved in cell signalling, binds to the cytoskel., to GPI or secreted no adhesion plaques (?) 2021/3/23 * 分布 刺激物 整合素配体 ICAM-1 激活 IL－1, WBC 上的 LFA-1 EC等 TNF, Mac-1 IFNr ICAM-2 EC等 WBC上的 LFA-1 VCAM-1 激活 IL－1, Mono上的 VLA-4 EC TNF Lymph上的VLA-4 2021/3/23 * 作用:与整合素一起,参与免疫、 炎症 反应,传递淋巴细胞的共刺激信号。 使淋巴细胞激活的信号: 抗原信号:第一信号 共刺激信号（第二信号）:由粘附分子介 导的信号。 B7-1－CD28, CTLA-4 2021/3/23 * （四）选择素家族（Selectin） 识别SLex的lectin(凝集素)的粘附分子。 单链,一次跨膜,胞外区从N端起依次为凝集素样区、表皮生长因子（EGF）样区和数个补体结合区。 配体为寡糖Slex、 Slea等 。 2021/3/23 * Major families of cell adhesion proteins. Cadherin are homophilic adhesion molecules Ig-superfamily are Ca2+ independent and participate in heterophilic and homophilic. Selectins bind carbohydrate groups on adjacent cells only in the presence of Ca2+ 2021/3/23 * Hynes: TiCB: 9:M33 1999 Cadherins Ca 2+ -dep. homophilic adhesion functional unit = dimer Immunoglobin superfamily (CAMs) homophilic or heterophilic Selectins heterophilic P selectin + counter-receptor PSGL-1, glycosylated Integrins heterodimers, heterophilic bind to ECM, Ig-CAMs, cadherins adhesion, polarity, migration Cadh. repeats Ig and Fn III repeats lectin repeats I-CAM CELL ADHESION MOLECULES CELL-CELL adhesion 2021/3/23 * 组成: L –S