Membrane association and polar localization of the Legionella pneumophila T4SS DotO ATPase mediated by two nonredundant receptors

• 成果类型: Article
• 署名作者: Vijayrajratnam, Sukhithasri; Milek, Sonja; Maggi, Stefano; Ashen, Kaleigh; Ferrell, Micah; Hasanovic, Ahmet; Holgerson, Agnieszka; Kannaiah, Shanmugapriya; Singh, Manpreet; Ghosal, Debnath; Jensen, Grant J.; Vogel, Joseph P.
• 署名单位: Washington University (WUSTL); University of Zurich; California Institute of Technology; Brigham Young University; Michigan State University; University of Melbourne; University of Melbourne
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-13660
• DOI: 10.1073/pnas.2401897121
• 发表日期: 2024-10-03
• 关键词: iv secretion system; legionnaires-disease; plasmid r388; virb4 atpase; c-terminus; protein; identification; biogenesis; bacterium; complex

摘要

The Legionella pneumophila Dot/Icm type IVB secretion system (T4BSS) is a large, multisubunit complex that exports a vast array of substrates into eukaryotic host cells. DotO, a distant homolog of the T4ASS ATPase VirB4, associates with the bacterial inner membrane despite lacking hydrophobic transmembrane domains. Employing a genetic approach, we found DotO's membrane association is mediated by three inner-membrane Dot/Icm components, IcmT, and a combined DotJ-DotI complex (referred to as DotJI). Although deletion of icmT or dotJI individually does not affect DotO's membrane association, the simultaneous inactivation of all three genes results in increased amounts of soluble DotO. Nevertheless, deleting each receptor separately profoundly affects positioning of DotO, disrupting its link with the Dot/Icm complex at the bacterial poles, rendering the receptors nonredundant. Furthermore, a collection of dotO point mutants that we isolated established that DotO's N-terminal domain interacts with the membrane receptors and is involved in dimerization, whereas DotO's C-terminal ATPase domain primarily contributes to the protein's formation of oligomers. Modeling data revealed the complex interaction between DotO and its receptors is responsible for formation of DotO's unique hexamer of dimers configuration, which is a defining characteristic of VirB4 family members.