Viral and Developmental Cell Fusion Mechanisms: Conservation and Divergence

Abstract

Membrane fusion is a fundamental requirement in numerous developmental, physiological, and pathological processes in eukaryotes. So far, only a limited number of viral and cellular fusogens, proteins that fuse membranes, have been isolated and characterized. Despite the diversity in structures and functions of known fusogens, some common principles of action apply to all fusion reactions. These can serve as guidelines in the search for new fusogens, and may allow the formulation of a cross-species, unified theory to explain divergent and convergent evolutionary principles of membrane fusion.

Cell fusion induced by ERVWE1 or measles virus causes cellular senescence

“…A variety of viruses that infect human populations, including HIV, MV, and the more widely spread respiratory syncytia virus and influenza, can induce cell fusion and formation of multinuclear cells following infection (Duelli and Lazebnik 2007). In addition, endogenous fusogens and even putative anti-cancer treatments can cause formation of syncytia (Sapir et al 2008;Tovar et al 2010). Our present findings suggest that cellular senescence functions as a protective mechanism that limits proliferation of the syncytia cells and might promote their immune surveillance.…”

“…Many viruses induce fusion of infected cells to support their reproduction and dissemination (Sapir et al 2008). The mammalian organism has found a way to use the fusogenic property of an endogenous virus that was incorporated into the genome during the course of evolution in order to function in placenta formation (Blond et al 2000;Mi et al 2000;Dupressoir et al 2011).…”

“…Overall, our results showed that cells fused by ERVWE1 expression demonstrate phenotypical and molecular characteristics of senescent cells. (Oldstone et al 1999;Sapir et al 2008;Delpeut et al 2012). We therefore investigated whether MV-induced fused cells show features of cellular senescence.…”

“…Moreover, intratumoral delivery of fusogenic agents or drugs that induce polyploidy has been suggested as a means of cancer treatment (Lin et al 2010;Tovar et al 2010). Cell fusion is an essential event in many developmental and physiological processes (Ogle et al 2005;Duelli and Lazebnik 2007;Sapir et al 2008). In mammals, cell fusion is vital for the proper functioning of muscles, osteoclasts, and the placenta.…”

“…In mammals, cell fusion is vital for the proper functioning of muscles, osteoclasts, and the placenta. The mechanism of physiological cell fusion relies on the activity of fusogenic proteins (fusogens) (Sapir et al 2008). Aberrant expression of fusogens in normal cells leads to unprogrammed illicit cell fusion (Duelli and Lazebnik 2007;Larsson et al 2008).…”