Phosphorylation of Nonmuscle myosin II-A regulatory light chain resists Sendai virus fusion with host cells.

Provas Das,Shamik Sen,Siddhartha S Jana,Sumit K Dey,Alakesh Das,Shekhar Saha,Debi P Sarkar,Sunandini Chandra,Mahua R Das

doi:10.1038/srep10395

Abstract

Enveloped viruses enter host cells through membrane fusion and the cells in turn alter their shape to accommodate components of the virus. However, the role of nonmuscle myosin II of the actomyosin complex of host cells in membrane fusion is yet to be understood. Herein, we show that both (−) blebbistatin, a specific inhibitor of nonmuscle myosin II (NMII) and small interfering RNA markedly augment fusion of Sendai virus (SeV), with chinese hamster ovary cells and human hepatocarcinoma cells. Inhibition of RLC phosphorylation using inhibitors against ROCK, but not PKC and MRCK, or overexpression of phospho-dead mutant of RLC enhances membrane fusion. SeV infection increases cellular stiffness and myosin light chain phosphorylation at two hour post infection. Taken together, the present investigation strongly indicates that Rho-ROCK-NMII contractility signaling pathway may provide a physical barrier to host cells against viral fusion.

Highlights

Isoforms of nonmuscle myosin heavy chain (NMHC) II, termed NMHC II-A, II-B and II-C, are encoded by three different genes[14]
No fusion was observed when heat-inactivated virion particles were used for the kinetic study or with active virions at 25 °C with 50 μ M (− ) blebbistatin treated CHO and Huh[7] cells, suggesting that virus-cell membrane fusion is dependent on the activity of nonmuscle myosin II (NMII) of host cells other than physiological temperature and activity of viral proteins
The key step in successful viral infection involves complete fusion at plasma membrane level that in turn, encompasses two closely associated important processes- membrane mixing and content mixing[29]. Both these processes are known to be catalyzed by two viral spike glycoproteins viz. HN protein and F protein, the fusion pore formation is currently known to be critically regulated by several host cell components

Summary

Introduction

Isoforms of nonmuscle myosin heavy chain (NMHC) II, termed NMHC II-A, II-B and II-C, are encoded by three different genes[14]. They play important roles in cellular functions such as cytokinesis, migration, and adhesion[15,16]. Their role in viral infection is yet to be explored. We investigate the participation of NMII isoforms of host cells in regulating viral fusion

Methods

Results

Conclusion