title: FlhG employs diverse intrinsic domains and influences FlhF GTPase activity to numerically regulate polar flagellar biogenesis in Campylobacter jejuni.
abstract: Flagellation in polar flagellates is one of the rare biosynthetic processes known to be numerically regulated in bacteria. Polar flagellates must spatially and numerically regulate flagellar biogenesis to create flagellation patterns for each species that are ideal for motility. FlhG ATPases numerically regulate polar flagellar biogenesis, yet FlhG orthologs are diverse in motif composition. We discovered that Campylobacter jejuni FlhG is at the center of a multipartite mechanism that likely influences a flagellar biosynthetic step to control flagellar number for amphitrichous flagellation, rather than suppressing activators of flagellar gene transcription as in Vibrio and Pseudomonas species. Unlike other FlhG orthologs, the FlhG ATPase domain was not required to regulate flagellar number in C. jejuni. Instead, two regions of C. jejuni FlhG that are absent or significantly altered in FlhG orthologs are involved in numerical regulation of flagellar biogenesis. Additionally, we found that C. jejuni FlhG influences FlhF GTPase activity, which may mechanistically contribute to flagellar number regulation. Our work suggests that FlhG ATPases divergently evolved in each polarly flagellated species to employ different intrinsic domains and extrinsic effectors to ultimately mediate a common output - precise numerical control of polar flagellar biogenesis required to create species-specific flagellation patterns optimal for motility.
authors.affiliation: Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA.
authors.forename: Connor J
authors.initials: CJ
authors.lastname: Gulbronson
authors.affiliation: Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA.
authors.forename: Deborah A
authors.initials: DA
authors.lastname: Ribardo
authors.affiliation: Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA.
authors.forename: Murat
authors.initials: M
authors.lastname: Balaban
authors.affiliation: LOEWE Center for Synthetic Microbiology (Synmikro) and Department of Chemistry, Philipps University Marburg, 35403, Marburg, Germany.
authors.forename: Carina
authors.initials: C
authors.lastname: Knauer
authors.affiliation: LOEWE Center for Synthetic Microbiology (Synmikro) and Department of Chemistry, Philipps University Marburg, 35403, Marburg, Germany.
authors.forename: Gert
authors.initials: G
authors.lastname: Bange
authors.affiliation: Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA.
authors.forename: David R
authors.initials: DR
authors.lastname: Hendrixson
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016123:Campylobacter jejuni / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism; D005407:Flagella / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D020559:Monomeric GTP-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017434:Protein Structure, Tertiary
chemical_list: D001426:Bacterial Proteins; C078317:flhF protein, Bacteria; D020559:Monomeric GTP-Binding Proteins