The crystal homotrimeric structures of the ectodomain (residues 1-422) of the mammalian rhabdovirus vesicular stomatitis virus (VSV) gpGVSV , were already reported on 2006-2007 . Both pre-(physiological pH) and low-pH induced post-fusion conformations were crystallographic solved for gpGVSV isolated by proteolisis of purified VSV virions. According to more recent crystallographic evidences derived from the Chandipura virus (CHAV) and rabies virus (RABV) , each mammalian gpG chain folds into fusion (FD), pleckstrin-homology (PH), and trimerization (TrD) domains. Shorter R1-R5 linkers connect the domains (Figure and Table ) . At the virion membrane surface, the gpGVSV monomeric chains folded into pre-fusion homotrimers 17 around a central top-tobottom cavity (Figure ). At the virion membrane surface, the lowering of pH triggers extensive conformational gpGVSV changes by refolding several R-linkers. By spring-loaded mechanisms, short α-helices of some R-linkers extend and refold favoring relative rotations between domains and induction of rigid six-α-helix bundles in the final post-fusion conformation, while maintaining the central trimer cavity. These mammalian rhabdoviral pre-to-post-fusion changes occur through reversible trimer-monomer-dimer-trimer pathway transitions , in contrast to the irreversibility of other enveloped viral gpGs. Particularly in gpGVSV, the low-pH induces refoldings of the R1, R5 and R4 linkers contributing to relative position changes of FD / TrD and extending the TrD α-helices from a R4-TrD interface (Figure , Figure ). The protonation of 60 H, 162 H, 407 H and 409 H gpGVSV residues may constitute sensitive pH switches to favour separation of R5 / FD towards their post-fusion conformation . At physiological high-pH, deprotonation of 268 D, 274 D, 395 D, and 393 D (and/or other acidic residues at R4 / R5), could destabilize the postfusion six-α-helix-bundles, favouring a back transition to their previous pre-fusion conformations . Many of those folding / fusion features were confirmed by the corresponding mutagenesis studies. Despite their amino acid sequence discrepancies, the trimer, 3-domain monomer folding (including disulphide pattern and Cystein domain borders), linkers and pH-dependent refolding transitions, were very similar among mammalian rhabdoviruses, whether gpG were obtained by virion protease digested gpGVSV or gpGCHAV or recombinant gpGRABV . However, such features are not yet completely understood for other rhabdoviruses.