title: Eukaryotic GPN-loop GTPases paralogs use a dimeric assembly reminiscent of archeal GPN.
abstract: GTPases are molecular switches that regulate a wide-range of cellular processes. The GPN-loop GTPase (GPN) is a sub-family of P-loop NTPase that evolved from a single gene copy in archaea to triplicate paralog genes in eukaryotes, each having a non-redundant essential function in cell. In Saccharomyces cerevisiae, yGPN1 and yGPN2 are involved in sister chromatid cohesion mechanism, whereas nothing is known regarding yGPN3 function. Previous high-throughput experiments suggested that GPN paralogs interaction may occur. In this work, GPN|GPN contact was analyzed in details using TAP-Tag approach, yeast two-hybrid assay, in silico energy computation and site-directed mutagenesis of a conserved Glu residue located at the center of the interaction interface. It is demonstrated that this residue is essential for cell viability. A chromatid cohesion assay revealed that, like yGPN1 and yGPN2, yGPN3 also plays a role in sister chromatid cohesion. These results suggest that all three GPN proteins act at the molecular level in sister chromatid cohesion mechanism as a GPN|GPN complex reminiscent of the homodimeric structure of PAB0955, an archaeal member of GPN-loop GTPase.
authors: CEA, iBEB, Service de Biochimie et Toxicologie Nucléaire/LBSP, Bagnols-sur-Cèze, France.
authors: Béatrice
authors: B
authors: Alonso
authors: Carole
authors: C
authors: Beraud
authors: Sarra
authors: S
authors: Meguellati
authors: Shu W
authors: SW
authors: Chen
authors: Jean Luc
authors: JL
authors: Pellequer
authors: Jean
authors: J
authors: Armengaud
authors: Christian
authors: C
authors: Godon
mesh_terms: D018797:Cell Cycle Proteins; D002842:Chromatids / Q000235:genetics / Q000378:metabolism*; D002868:Chromosomal Proteins, Non-Histone; D020558:GTP Phosphohydrolases / Q000378:metabolism*; D019204:GTP-Binding Proteins / Q000378:metabolism*; D020559:Monomeric GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D016297:Mutagenesis, Site-Directed; D017434:Protein Structure, Tertiary; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D020798:Two-Hybrid System Techniques
chemical_list: D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; C582594:GPN2 protein, S cerevisiae; C582595:GPN3 protein, S cerevisiae; D020558:GTP Phosphohydrolases; D019204:GTP-Binding Proteins; C568359:Npa3 protein, S cerevisiae; D020559:Monomeric GTP-Binding Proteins
keywords: GPN-loop-GTPase; P-loop NTPase; chromatid cohesion; heterodimer; paralogous interactions