title: Presence of calcium-binding motifs in PilY1 homologs correlates with Ca-mediated twitching motility and evolutionary history across diverse bacteria.
abstract: Twitching motility, involving type IV pili, is essential for host colonization and virulence of many pathogenic bacteria. Studies of PilY1, a tip-associated type IV pili protein, indicate that PilY1 functions as a switch between pilus extension and retraction, resulting in twitching motility. Recent work detected a calcium-binding motif in PilY1 of some animal bacterial pathogens and demonstrated that binding of calcium to PilY1 with this motif regulates twitching. Though studies of PilY1 in non-animal pathogens are limited, our group demonstrated that twitching motility in the plant pathogen Xylella fastidiosa, which contains three PilY1 homologs, is increased by calcium supplementation. A study was conducted to investigate the phylogenetic relationship between multiple PilY1 homologs, the presence of calcium-binding motifs therein, and calcium-mediated twitching motility across diverse bacteria. Strains analyzed contained one to three PilY1 homologs, but phylogenetic analyses indicated that PilY1 homologs containing the calcium-binding motif Dx[DN]xDGxxD are phylogenetically divergent from other PilY1 homologs. Plant-associated bacteria included in these analyses were then examined for a calcium-mediated twitching response. Results indicate that bacteria must have at least one PilY1 homolog containing the Dx[DN]xDGxxD motif to display a calcium-mediated increase in twitching motility, which likely reflects an adaption to environmental calcium concentrations.
authors: Department of Entomology and Plant Pathology, Auburn University, Auburn, AL 36849, USA.
authors: Jennifer K
authors: JK
authors: Parker
authors: Department of Entomology and Plant Pathology, Auburn University, Auburn, AL 36849, USA.
authors: Luisa F
authors: LF
authors: Cruz
authors: Department of Entomology and Plant Pathology, Auburn University, Auburn, AL 36849, USA.
authors: Michael R
authors: MR
authors: Evans
authors: Department of Entomology and Plant Pathology, Auburn University, Auburn, AL 36849, USA lzd0005@auburn.edu.
authors: Leonardo
authors: L
authors: De La Fuente
mesh_terms: D020816:Amino Acid Motifs; D018407:Bacterial Physiological Phenomena; D002118:Calcium / Q000378:metabolism*; D036781:Fimbriae Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D010861:Fimbriae, Bacterial / Q000502:physiology*; D014644:Genetic Variation; D009068:Movement; D010802:Phylogeny; D010944:Plants / Q000382:microbiology; D016415:Sequence Alignment; D044167:Xylella / Q000235:genetics / Q000502:physiology*
chemical_list: D036781:Fimbriae Proteins; D002118:Calcium
keywords: bacteria; calcium; pilY1 homologs; twitching; type IV pili