Mannose 6-Phosphate Receptors and ADP-ribosylation Factors Cooperate for High Affinity Interaction of the AP-1 Golgi Assembly Proteins with Membranes (*)
Mannose 6-Phosphate Receptors and ADP-ribosylation Factors Cooperate for High Affinity Interaction of the AP-1 Golgi Assembly Proteins with Membranes (*)
复制标题
甘露糖 6-磷酸受体和 ADP-核糖基化因子协同作用，实现 AP-1 高尔基体组装蛋白与膜的高亲和力相互作用 (*)
DOI：
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发表时间：
1996
影响因子：
4.8
通讯作者：
B. Hoflack
中科院分区：
文献类型：
--
作者：
R. L. Borgne;G. Griffiths;B. Hoflack
跨高尔基体网络中的网格蛋白外壳组装，导致甘露糖 6-磷酸受体 (MPR) 被隔离到新生囊泡中，需要 ARF-1 依赖的胞质 AP-1 高尔基体组装蛋白易位到该细胞器的膜上。 MPR（即货物分子）在涂层组装中的机制作用目前尚不清楚。使用 GTP 依赖性、布雷菲德菌素 A 敏感的体外 AP-1 结合测定，我们在此确定了 AP-1 结合反应的参数。我们证明，除了 ARF-1 之外，MPR 还有助于创建高亲和力 AP-1 结合位点 (K ≈ 25 nM)，因为它们的数量与 MPR 阴性细胞中表达的 MPR 分子数量相关。定量电子显微镜显示，这些高亲和力结合位点存在于跨高尔基体网络膜上，正如预期的那样，并且在某种程度上存在于早期内体上。当 MPR 或 ARF-1 成为限速成分时，高亲和力结合位点就会丢失。相反，GTPS（鸟苷 5'-O-（3-硫代三磷酸））可增加膜结合 ARF-1 的量，主要发现跨高尔基体网络膜上的低亲和力 AP-1 结合位点 (K ≈ 150 nM)，通常在其不存在时检测不到。总的来说，这些结果表明 MPR 分选与外壳组装的第一步高度耦合，并且 MPR、ARF-1 和可能的其他蛋白质合作实现 AP-1 的高亲和力相互作用。
Clathrin coat assembly in the trans-Golgi network, leading to the sequestration of the mannose 6-phosphate receptors (MPRs) into nascent vesicles, requires the ARF-1-dependent translocation of the cytosolic AP-1 Golgi assembly proteins onto the membranes of this organelle. The mechanistic role of the MPRs, i.e. the cargo molecules, in coat assembly is at present unclear. Using a GTP-dependent, brefeldin A-sensitive in vitro AP-1 binding assay, we have determined here the parameters of the AP-1 binding reaction. We demonstrate that, in addition of ARF-1, the MPRs contribute to create high affinity AP-1 binding sites (K ≈ 25 nM), since their number correlates the number of MPR molecules expressed in MPR-negative cells. The quantitative electron microscopy shows that these high affinity binding sites are present on trans-Golgi network membranes, as expected, and to some extent on early endosomes. The high affinity binding sites are lost when the MPRs or ARF-1 become rate-limiting components. Conversely, GTPS (guanosine 5′-O-(3-thiotriphosphate)), which increases the amount of membrane-bound ARF-1, mostly uncovers low affinity AP-1 binding sites (K ≈ 150 nM) on trans-Golgi network membranes, normally not detected in its absence. Collectively, these results argue that MPR sorting is highly coupled to the first step of coat assembly and that the MPRs, ARF-1, and possibly other proteins cooperate for high affinity interactions of AP-1.
ADP-核糖基化因子是内质网和顺式高尔基体之间的囊泡运输所必需的。
DOI：
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发表时间：
1992
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Balch,WE;Kahn,RA;Schwaninger,R
通讯作者：
Schwaninger,R