Fan Long, Liu Li, Zhu Cuicui, Zhu Qingyi, Lu Shan, Liu Ping
Jiangsu Province Key Laboratory for Molecular and Medicine Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing 210023, China.
Laboratory of Molecular Biology, Jiangsu Province Hospital of Traditional Chinese Medicine, Nanjing 210029, China.
Int J Mol Sci. 2016 May 26;17(6):818. doi: 10.3390/ijms17060818.
Bst-2 (bone marrow stromal cell antigen 2) is a type II membrane protein, and it acts as a tetherin to inhibit virion releasing from infectious cells. Membrane type-1 matrix metalloproteinase (MT1-MMP) is a protease. It plays a pivotal role in cellular growth and migration by activating proMMP-2 into active MMP2. Our results here elaborate that MT1-MMP inhibits the tetherin activity of Bst-2 by interacting with Bst-2, and the cytoplasmic domains of both Bst-2 and MT1-MMP play critical roles within this interaction. Based on our experimental data, the assays for virion release and co-immunoprecipitation have clearly demonstrated that the activity of Bst-2 is markedly inhibited by MT1-MMP via their interaction; and both the N-terminal domain of Bst-2 and the C-terminal domain of MT1-MMP are important in the interaction. Immunostaining and Confocal Microscopy assay shows that MT1-MMP interacts with Bst-2 to form granular particles trafficking into cytoplasm from membrane and, finally, results in Bst-2 and MT1-MMP both being inhibited. In addition, mutant experiments elucidate that the N-terminal domain of Bst-2 is not only important in relating to the activity of Bst-2 itself, but is important for inhibiting the MT1-MMP/proMMP2/MMP2 pathway. These findings suggest that MT1-MMP is a novel inhibitor of Bst-2 in MT1-MMP expressed cell lines and also indicate that both the N-terminal domain of Bst-2 and the C-terminal domain of MT1-MMP are crucial in down-regulation.
Bst-2（骨髓基质细胞抗原2）是一种II型膜蛋白，作为一种束缚素，可抑制病毒粒子从感染细胞中释放。膜型1基质金属蛋白酶（MT1-MMP）是一种蛋白酶。它通过将前MMP-2激活为活性MMP2，在细胞生长和迁移中起关键作用。我们在此的研究结果表明，MT1-MMP通过与Bst-2相互作用抑制Bst-2的束缚素活性，并且Bst-2和MT1-MMP的细胞质结构域在这种相互作用中起关键作用。基于我们的实验数据，病毒粒子释放测定和免疫共沉淀实验清楚地表明，MT1-MMP通过它们之间的相互作用显著抑制Bst-2的活性；Bst-2的N端结构域和MT1-MMP的C端结构域在这种相互作用中都很重要。免疫染色和共聚焦显微镜检测显示，MT1-MMP与Bst-2相互作用形成颗粒状物质，从细胞膜转运至细胞质中，最终导致Bst-2和MT1-MMP均受到抑制。此外，突变实验表明，Bst-2的N端结构域不仅对Bst-2自身的活性很重要，而且对抑制MT1-MMP/前MMP2/MMP2途径也很重要。这些发现表明，在表达MT1-MMP的细胞系中，MT1-MMP是Bst-2的一种新型抑制剂，也表明Bst-2的N端结构域和MT1-MMP的C端结构域在下调过程中都至关重要。
