ROCK1 and LIM Kinase Modulate Retrovirus Particle Release and Cell-Cell Transmission Events

• Authors: Xiaoyun Wen, Childrens Healthcare Atlanta; Lingmei Ding, Childrens Healthcare Atlanta; Jaang-Jiun Wang, Emory University; Mingli Qi, Emory University; Jason Hammonds, Emory University; Hin Chu, University of Hong Kong; Xuemin Chen, Emory University; Eric Hunter, Emory University; Paul Spearman, Emory University
• Journal Title: Journal of Virology
• Volume: Volume 88, Number 12
• Publisher: American Society for Microbiology | 2014-06-01, Pages 6906-6921
• Type of Work: Article | Final Publisher PDF
• Publisher DOI: http://doi.org/10.1128/JVI.00023-14
• Subjects: Biology, Microbiology; Health Sciences, Immunology; Health Sciences, General
• Keywords: Science & Technology; Life Sciences & Biomedicine; Virology; VIROLOGY; HUMAN-IMMUNODEFICIENCY-VIRUS; PFIZER MONKEY VIRUS; CD4 T-CELLS; ACTIN-FILAMENTS; INTRACELLULAR TRAFFICKING; COFILIN PHOSPHORYLATION; MEMBRANE INTERACTIONS; HOST-CELLS; HIV-1 GAG; TYPE-1

Abstract

The assembly and release of retroviruses from the host cells require dynamic interactions between viral structural proteins and a variety of cellular factors. It has been long speculated that the actin cytoskeleton is involved in retrovirus production, and actin and actin-related proteins are enriched in HIV-1 virions. However, the specific role of actin in retrovirus assembly and release remains unknown. Here we identified LIM kinase 1 (LIMK1) as a cellular factor regulating HIV-1 and Mason-Pfizer monkey virus (M-PMV) particle release. Depletion of LIMK1 reduced not only particle output but also virus cell-cell transmission and was rescued by LIMK1 replenishment. Depletion of the upstream LIMK1 regulator ROCK1 inhibited particle release, as did a competitive peptide inhibitor of LIMK1 activity that prevented cofilin phosphorylation. Disruption of either ROCK1 or LIMK1 led to enhanced particle accumulation on the plasma membrane as revealed by total internal reflection fluorescence microscopy (TIRFM). Electron microscopy demonstrated a block to particle release, with clusters of fully mature particles on the surface of the cells. Our studies support a model in which ROCK1-and LIMK1-regulated phosphorylation of cofilin and subsequent local disruption of dynamic actin turnover play a role in retrovirus release from host cells and in cell-cell transmission events.