The Hantaan Virus Glycoprotein Precursor Is Cleaved at the Conserved Pentapeptide WAASA

AbstractThe medium segment of the tripartite negative-stranded RNA genome of hantaviruses encodes for the predicted glycoprotein precursor GPC. We have demonstrated here the expression of the glycoprotein precursor of Hantaan virus following transfection of mammalian cells. The cleavage of the precursor into the glycoproteins G1 and G2 followed the rules for signal peptides and seemed to occur directly at the pentapeptide motif “WAASA.” Our data indicate that the signal peptidase complex is responsible for the proteolytic processing of the precursor GPC of Hantaan virus. The comparison of this region of the glycoprotein precursor, including the absolutely conserved WAASA motif, suggests a similar cleavage event for all hantavirus glycoproteins

PilY1 and minor pilins form a complex priming the type IVa pilus in Myxococcus xanthus

Type IVa pili are ubiquitous and versatile bacterial cell surface filaments that undergo cycles of extension, adhesion and retraction powered by the cell-envelope spanning type IVa pilus machine (T4aPM). The overall architecture of the T4aPM and the location of 10 conserved core proteins within this architecture have been elucidated. Here, using genetics, cell biology, proteomics and cryo-electron tomography, we demonstrate that the PilY1 protein and four minor pilins, which are widely conserved in T4aP systems, are essential for pilus extension in Myxococcus xanthus and form a complex that is an integral part of the T4aPM. Moreover, these proteins are part of the extended pilus. Our data support a model whereby the PilY1/minor pilin complex functions as a priming complex in T4aPM for pilus extension, a tip complex in the extended pilus for adhesion, and a cork for terminating retraction to maintain a priming complex for the next round of extension

PilY1 and minor pilins form a complex priming the type IVa pilus in Myxococcus xanthus

Type IVa pili are ubiquitous and versatile bacterial cell surface filaments that undergo cycles of extension, adhesion and retraction powered by the cell-envelope spanning type IVa pilus machine (T4aPM). The overall architecture of the T4aPM and the location of 10 conserved core proteins within this architecture have been elucidated. Here, using genetics, cell biology, proteomics and cryo-electron tomography, we demonstrate that the PilY1 protein and four minor pilins, which are widely conserved in T4aP systems, are essential for pilus extension in Myxococcus xanthus and form a complex that is an integral part of the T4aPM. Moreover, these proteins are part of the extended pilus. Our data support a model whereby the PilY1/minor pilin complex functions as a priming complex in T4aPM for pilus extension, a tip complex in the extended pilus for adhesion, and a cork for terminating retraction to maintain a priming complex for the next round of extension