Yu-Yuan Zhang,Ronghui Liang,Shu-Jie Wang,Zi-Wei Ye,Tong-Yun Wang,Meng Chen,Jianbo Liu,Lei Na,Yue-Lin Yang,Yong-Bo Yang,Shuofeng Yuan,Xin Yin,Xue-Hui Cai,Yan-Dong Tang

J Biol Chem.2022 Sep 19;298(11):102511.doi: 10.1016/j.jbc.2022.102511. Online ahead of print.

Abstract

Revealing the mechanisms of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) entry and cell-to-cell spread might provide insights for understanding the underlying mechanisms of viral pathogenesis, tropism, and virulence. The signaling pathways involved in SARS-CoV-2 entry and viral spike-mediated cell-to-cell fusion remain elusive. In the current study, we found that macropinocytosis inhibitors significantly suppressed SARS-CoV-2 infection at both the entry and viral spike-mediated cell-to-cell fusion steps. We demonstrated that SARS-CoV-2 entry required the small GTPase Rac1 and its effector kinase p21-activated kinase 1 by dominant-negative and RNAi assays in human embryonic kidney 293T-angiotensin-converting enzyme 2 cells and that the serine protease transmembrane serine protease 2 reversed the decrease in SARS-CoV-2 entry caused by the macropinocytosis inhibitors. Moreover, in the cell-to-cell fusion assay, we confirmed that macropinocytosis inhibitors significantly decreased viral spike-mediated cell-to-cell fusion. Overall, we provided evidence that SARS-CoV-2 utilizes a macropinocytosis pathway to enter target cells and to efficiently promote viral spike-mediated cell-to-cell fusion.

Keywords: SARS-CoV-2; cell-to-cell; entry; fusion; macropinocytosis.