Acinetobacter baylyi regulates type IV pilus synthesis by employing two extension motors and a motor protein inhibitor. Author Courtney Ellison, Triana Dalia, Catherine Klancher, Joshua Shaevitz, Zemer Gitai, Ankur Dalia Publication Year 2021 Type Journal Article Abstract Bacteria use extracellular appendages called type IV pili (T4P) for diverse behaviors including DNA uptake, surface sensing, virulence, protein secretion, and twitching motility. Dynamic extension and retraction of T4P is essential for their function, and T4P extension is thought to occur through the action of a single, highly conserved motor, PilB. Here, we develop Acinetobacter baylyi as a model to study T4P by employing a recently developed pilus labeling method. By contrast to previous studies of other bacterial species, we find that T4P synthesis in A. baylyi is dependent not only on PilB but also on an additional, phylogenetically distinct motor, TfpB. Furthermore, we identify a protein (CpiA) that inhibits T4P extension by specifically binding and inhibiting PilB but not TfpB. These results expand our understanding of T4P regulation and highlight how inhibitors might be exploited to disrupt T4P synthesis. Keywords Gene Expression Regulation, Bacterial, Biological Transport, Virulence, Molecular Motor Proteins, Fimbriae Proteins, Fimbriae, Bacterial, Acinetobacter Journal Nat Commun Volume 12 Issue 1 Pages 3744 Date Published 2021 Jun 18 ISSN Number 2041-1723 DOI 10.1038/s41467-021-24124-6 Alternate Journal Nat Commun PMCID PMC8213720 PMID 34145281 PubMedPubMed CentralGoogle ScholarBibTeXEndNote X3 XML