Myxococcus xanthus PilB interacts with c-di-GMP and modulates motility and biofilm formation

The regulation of biofilm and motile states as alternate bacterial lifestyles has been studied extensively in flagellated bacteria, where the second messenger cyclic-di-GMP (cdG) plays a crucial role. However, much less is known about the mechanisms of such regulation in motile bacteria without flagella. The bacterial type IV pilus (T4P) serves as a motility apparatus that enables Myxococcus xanthus to move on solid surfaces. PilB, the T4P assembly ATPase, is, therefore, required for T4P-dependent motility in M. xanthus. Interestingly, T4P is also involved in the regulation of exopolysaccharide as the biofilm matrix material in this bacterium. A newly discovered cdG-binding domain, MshEN, is conserved in the N-terminus of PilB (PilBN) in M. xanthus and other bacteria. This suggests that cdG may bind to PilB to control the respective outputs that regulate biofilm development and T4P-powered motility. In this study, we aimed to validate M. xanthus PilB as a cdG effector protein. We performed a systematic mutational analysis of its cdG-binding domain to investigate its relationship with motility, piliation, and biofilm formation. Excluding those resulting in low levels of PilB protein, all other substitution mutations in PilBN resulted in pilB mutants with distinct and differential phenotypes in piliation and biofilm levels in M. xanthus. This suggests that the PilBN domain plays dual roles in modulating motility and biofilm levels, and these two functions of PilB can be dependent on and independent of each other in M. xanthus. IMPORTANCE The regulation of motility and biofilm by cyclic-di-GMP in flagellated bacteria has been extensively investigated. However, our knowledge regarding this regulation in motile bacteria without flagella remains limited. Here, we aimed to address this gap by investigating a non-flagellated bacterium with motility powered by bacterial type-IV pilus (T4P). Previous studies hinted at the possibility of Myxococcus xanthus PilB, the T4P assembly ATPase, serving as a cyclic-di-GMP effector involved in regulating both motility and biofilm. Our findings strongly support the hypothesis that PilB directly interacts with cyclic-di-GMP to act as a potential switch to promote biofilm formation or T4P-dependent motility. These results shed light on the bifurcation of PilB functions and its pivotal role in coordinating biofilm formation and T4P-mediated motility.

Medienart:	E-Artikel

Erscheinungsjahr:	2023
Erschienen:	2023

Enthalten in:	Zur Gesamtaufnahme - volume:205
Enthalten in:	Journal of bacteriology - 205(2023), 9 vom: 26. Sept., Seite e0022123

Sprache:	Englisch

Beteiligte Personen:	Dye, Keane J [VerfasserIn] Salar, Safoura [VerfasserIn] Allen, Uvina [VerfasserIn] Smith, Wraylyn [VerfasserIn] Yang, Zhaomin [VerfasserIn]

Links:	Volltext

Themen:	61093-23-0 Adenosine Triphosphatases Biofilm Bis(3',5')-cyclic diguanylic acid Cyclic GMP Cyclic-di-GMP EC 3.6.1.- H2D2X058MU Journal Article Motility PilB ATPase Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, Non-P.H.S. Type IV pilus (T4P)

Anmerkungen:	Date Completed 27.09.2023 Date Revised 03.10.2023 published: Print-Electronic Citation Status MEDLINE

doi:	10.1128/jb.00221-23

funding:
Förderinstitution / Projekttitel:

PPN (Katalog-ID):	NLM361932928