Normally, HIV-1 enters into CD4+ cells through membrane fusion, and newly synthesized HIV-1 viral proteins assemble on the plasma membrane to form viral particles and bud out. In the previous study, we found host factor coiled-coil domain containing protein 8 (CCDC8) can strongly inhibit HIV-1 production, but the underline mechanism is not clear. Here we show that overexpression of CCDC8 reverses the normal HIV-1 production process, and causes newly assembled HIV-1 Gag particles to be endocytosed on the plasma membrane, rather than budding out. Live-cell imaging system captured the moment of CCDC8-mediated Gag internalization on the plasma membrane, and the speed of Gag turnover is up to 1.53 μm/s, much faster than Gag assembly on the plasma membrane. After Gag internalization, it accumulates in the cellular organelle—lysosome for degradation, but not proteasome, autophagosome, endoplasmic reticulum, clathrin or recycling endosome. In addition, CCDC8 is a membrane-associated protein, and N-terminal of CCDC8 is very important for membrane binding, and also important for inhibition of Gag assembly. C-terminal deletion of CCDC8 has a little effect on anti-HIV-1 effect. Moreover, CCDC8 is phosphorylated at amino acid threonine T87 and serine S261, and mono-methylated at lysine K491. Alanine mutations of T87A, S261A and K491A singly or in combination do not affect CCDC8 anti-HIV activity. In conclusion, overexpression of CCDC8 can cause newly assembled HIV-1 Gag particles on the plasma membrane to be endocytosed and degraded in lysosome.

通常，HIV-1通过膜融合进入CD4 +细胞，新合成的HIV-1病毒蛋白在质膜上聚集形成病毒颗粒并萌芽。在先前的研究中，我们发现包含宿主因子的卷曲螺旋结构域蛋白8（CCDC8）可以强烈抑制HIV-1的产生，但其下划线机制尚不清楚。在这里，我们显示CCDC8的过表达逆转了正常的HIV-1生产过程，并导致新组装的HIV-1 Gag颗粒被内吞在质膜上，而不是萌芽。活细胞成像系统捕获了CCDC8介导的Gag在质膜上内在化的瞬间，Gag周转速度高达1.53μm/ s，比在质膜上的Gag组装要快得多。Gag内化后，会积聚在细胞器中-溶酶体降解，但不包括蛋白酶体，自噬体，内质网，网格蛋白或回收内体。此外，CCDC8是一种膜相关蛋白，CCDC8的N端对于膜结合非常重要，对于抑制Gag装配也很重要。CCDC8的C端缺失对抗HIV-1的影响很小。此外，CCDC8在氨基酸苏氨酸T87和丝氨酸S261处被磷酸化，在赖氨酸K491处被单甲基化。T87A，S261A和K491A的丙氨酸突变单独或组合不影响CCDC8的抗HIV活性。总之，CCDC8的过度表达可导致质膜上新组装的HIV-1 Gag颗粒被内吞并在溶酶体中降解。CCDC8的N端对于膜结合非常重要，对抑制Gag装配也很重要。CCDC8的C端缺失对抗HIV-1的影响很小。此外，CCDC8在氨基酸苏氨酸T87和丝氨酸S261处被磷酸化，在赖氨酸K491处被单甲基化。T87A，S261A和K491A的丙氨酸突变单独或组合不影响CCDC8的抗HIV活性。总之，CCDC8的过度表达可导致质膜上新组装的HIV-1 Gag颗粒被内吞并在溶酶体中降解。CCDC8的N端对于膜结合非常重要，对抑制Gag装配也很重要。CCDC8的C端缺失对抗HIV-1的影响很小。此外，CCDC8在氨基酸苏氨酸T87和丝氨酸S261处被磷酸化，在赖氨酸K491处被单甲基化。T87A，S261A和K491A的丙氨酸突变单独或组合不影响CCDC8的抗HIV活性。总之，CCDC8的过度表达可导致质膜上新组装的HIV-1 Gag颗粒被内吞并在溶酶体中降解。T87A，S261A和K491A的丙氨酸突变单独或组合不影响CCDC8的抗HIV活性。总之，CCDC8的过度表达可导致质膜上新组装的HIV-1 Gag颗粒被内吞并在溶酶体中降解。T87A，S261A和K491A的丙氨酸突变单独或组合不影响CCDC8的抗HIV活性。总之，CCDC8的过表达可导致质膜上新组装的HIV-1 Gag颗粒被内吞并在溶酶体中降解。