Linked domain architectures allow for specialization of function in the FtsK/SpoIIIE ATPases of ESX secretion systems.

Published

Journal Article

Among protein secretion systems, there are specialized ATPases that serve different functions such as substrate recognition, substrate unfolding, and assembly of the secretory machinery. ESX (early secretory antigen target 6 kDa secretion) protein secretion systems require FtsK/SpoIIIE family ATPases but the specific function of these ATPases is poorly understood. The ATPases of ESX secretion systems have a unique domain architecture among proteins of the FtsK/SpoIIIE family. All well-studied FtsK family ATPases to date have one ATPase domain and oligomerize to form a functional molecular machine, most commonly a hexameric ring. In contrast, the ESX ATPases have three ATPase domains, encoded either by a single gene or by two operonic genes. It is currently unknown which of the ATPase domains is catalytically functional and whether each domain plays the same or a different function. Here we focus on the ATPases of two ESX systems, the ESX-1 system of Mycobacterium tuberculosis and the yuk system of Bacillus subtilis. We show that ATP hydrolysis by the ESX ATPase is required for secretion, suggesting that this enzyme at least partly fuels protein translocation. We further show that individual ATPase domains play distinct roles in substrate translocation and complex formation. Comparing the single-chain and split ESX ATPases, we reveal differences in the requirements of these unique secretory ATPases.

Full Text

Cited Authors

  • Ramsdell, TL; Huppert, LA; Sysoeva, TA; Fortune, SM; Burton, BM

Published Date

  • March 2015

Published In

Volume / Issue

  • 427 / 5

Start / End Page

  • 1119 - 1132

PubMed ID

  • 24979678

Pubmed Central ID

  • 24979678

Electronic International Standard Serial Number (EISSN)

  • 1089-8638

International Standard Serial Number (ISSN)

  • 0022-2836

Digital Object Identifier (DOI)

  • 10.1016/j.jmb.2014.06.013

Language

  • eng