Caveolae provide a specialized membrane environment for respiratory syncytial virus assembly.

Alexander Ludwig,Daniel Leong,Tra Huong Nguyen,Sara Sandin,Boon Huan Tan,Laxmi Iyer Ravi,Richard J Sugrue

doi:10.1242/jcs.198853

Abstract

ABSTRACTRespiratory syncytial virus (RSV) is an enveloped virus that assembles into filamentous virus particles on the surface of infected cells. Morphogenesis of RSV is dependent upon cholesterol-rich (lipid raft) membrane microdomains, but the specific role of individual raft molecules in RSV assembly is not well defined. Here, we show that RSV morphogenesis occurs within caveolar membranes and that both caveolin-1 and cavin-1 (also known as PTRF), the two major structural and functional components of caveolae, are actively recruited to and incorporated into the RSV envelope. The recruitment of caveolae occurred just prior to the initiation of RSV filament assembly, and was dependent upon an intact actin network as well as a direct physical interaction between caveolin-1 and the viral G protein. Moreover, cavin-1 protein levels were significantly increased in RSV-infected cells, leading to a virus-induced change in the stoichiometry and biophysical properties of the caveolar coat complex. Our data indicate that RSV exploits caveolae for its assembly, and we propose that the incorporation of caveolae into the virus contributes to defining the biological properties of the RSV envelope.

Highlights

Respiratory syncytial virus (RSV) is a leading cause of lower respiratory tract infection in young children
DISCUSSION caveolin-1 was previously shown to be sequestered into RSV filaments during virus morphogenesis (Brown et al, 2002a,b; Kipper et al, 2015), it was unclear whether this association was dependent or independent of caveolae
We have shown that RSV morphogenesis occurs within caveolae, and that caveolae are actively recruited to and incorporated into the growing RSV envelope

Summary

Introduction

Respiratory syncytial virus (RSV) is a leading cause of lower respiratory tract infection in young children. The assembly of RSV takes place on the surface of infected cells, where the viral ribonucleoproteins (RNPs) are packaged into filamentous particles that are bounded by a viral envelope (Bachi and Howe, 1973; Bachi, 1988; Santangelo and Bao, 2007; Roberts et al, 1995). Many molecular aspects of the virus assembly process have been defined

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