Mechanisms for regulation of intracellular protein sorting mediated by the adaptor protein (AP) complex family

衔接蛋白（AP）复合物家族介导的细胞内蛋白质分选调节机制

• 批准号: 12480178
• 负责人: OHNO Hiroshi
• 金额: $ 9.34万
• 依托单位: Kanazawa University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-12480178/
• 关键词: epithelial cells; selective sorting; μ1B; pliovirus receptor; axis of cell division; μ3B; seizure; ポリオウィルス受容体; AP複合体; エンドサイトーシス; リソソーム; 輸送シグナル; チロシン・シグナル; ジ-ロイシン・シグナル; 遺伝子欠損マウス

Plasma membrane (PM) of epithelial cells is physically divided by the tight junction into apical and basolateral domains, and distinct subsets of membrane proteins are expressed on the two domains. We cloned a new μ homologue, μlB, which is expressed exclusively in epithelial cells. AP-1B, containing μ1B, mediates selective sorting of newly synthesized proteins to the basolateral PM. There are two isoforms for poliovirus receptor (PVR), α and δ. We have found that PVRα interacts with μlB and expressed basolaterally, whereas PVRδ is not recognized by μ1B and randomly expressed on both PM domains. We also found that μ1B- deficient epithelial cells divide randomly, causing multi-layer morphology instead of monolayer characteristic to epithelial cells. In order to investigate the roles of μlB in organisms, we established ES cell lines for making μ1B knockout mice.We also established mice lacking μ3B, a subunit of the neuron-specific AP -3B complex. μ3B KO mice suffer from epileptic seizure. In these mice, KCl-stimulated release of GABA, an inhibitory neurotransmitter, from hippocampal slices decreased to one-half of that of wild-type mice, suggesting that break down in inhibitory synaptic transmission cause the seizure.

上皮细胞的质膜（PM）在物理上被紧密连接分为顶端和底外侧结构域，不同的膜蛋白亚群在这两个结构域上表达。我们克隆了一个新的μ同系物μ lb，它只在上皮细胞中表达。AP-1B含有μ1B，介导新合成蛋白对基底侧PM的选择性分选。脊髓灰质炎病毒受体（PVR）有α和δ两种亚型。我们发现PVRα与μlB相互作用并在基底侧表达，而PVRδ不被μ1B识别，在两个PM结构域上随机表达。我们还发现，缺乏μ1B的上皮细胞分裂是随机的，导致上皮细胞呈现多层形态，而不是单层的特征。为了研究μlB在生物体中的作用，我们建立了制备μ1B敲除小鼠的ES细胞系。我们还建立了缺乏μ3B的小鼠，μ3B是神经元特异性AP -3B复合物的一个亚基。μ3B KO小鼠出现癫痫发作。在这些小鼠中，kcl刺激海马切片中GABA（一种抑制性神经递质）的释放减少到野生型小鼠的一半，表明抑制性突触传递的中断导致了癫痫发作。

项目成果

Aguilar, R. C.: "Signal-binding specificity of the μ4 subunit of the adaptor protein complex, AP-4"J. Biol. Chem.. 276. 13145-13152 (2001)

Aguilar, R. C.：“接头蛋白复合物 AP-4 的 μ4 亚基的信号结合特异性”J. Biol. Chem.. 276. 13145-13152 (2001)

Eskelinen, E.-L.: "The polarized epithelia specific μ1B-adaptin complements u1A-deficiency in fibroblasts"EMBO report. (in press).

Eskelinen, E.-L.：“极化上皮特异性 μ1B-适应素可补充成纤维细胞中的 u1A 缺陷”EMBO 报告（正在出版）。

Eskelinen, E.-L.: "The polarized epithelia specific m1B-adaptin complements u1A-deficiency in fibroblasts"EMBO report. (in press).

Eskelinen, E.-L.：“极化上皮特异性 m1B-适应素可补充成纤维细胞中 u1A 的缺陷”EMBO 报告。

Blum stein, J.: "The neuronal form of AP-3 is required for synaptic vesicle formation from endosomes"J. Neurosci.. 21. 8034-8042 (2001)

Blum stein, J.：“AP-3 的神经元形式是内体形成突触小泡所必需的”J.

Ohka,S: "Basolateral sorting of human poliovirus receptor a involves an interaction with the μlB subunit of the clathrin adaptor complex in polarized epithelial cells"Biochem. Biophys. Res. Commun.. 287. 941-948 (2001)

Ohka, S：“人脊髓灰质炎病毒受体 a 的基底外侧分选涉及与极化上皮细胞中网格蛋白接头复合物的 μB 亚基的相互作用”Biochem. Commun. 287. 941-948 (2001)