Poster Presentation Australian Society for Microbiology Annual Scientific Meeting 2022

The diversity, conservation, and potential multifunctionality of archaeal tubulins (#115)

Hannah J Brown 1 , Iain G Duggin 1
  1. Australian Institute for Microbiology and Infection, University of Technology Sydney, Sydney, NSW, Australia

Tubulins are a superfamily of cytoskeletal proteins that are conserved across all domains of life. They provide structure and organisation to the cell, and are important for a range of cellular processes, including cell division, chromosome segregation, cell motility and migration, and intracellular transport of cargo such as signalling molecules, membrane components, and organelles. Tubulins and their associated proteins have been heavily investigated in Bacteria and Eukaryotes, but little is known about archaeal tubulins. Two main families of tubulins have been identified in archaea, including FtsZs[1], a key cell division protein well characterised in bacteria; and CetZs[2], an archaea-specific family. The CetZs have been implicated in cell shape control and motility in the shape-shifting model archaeon Haloferax volcanii[2,3], but beyond this, little is known about how CetZs may function in other roles or in other archaea.  We carried out phylogenetic analysis of CetZs from across all archaeal species and identified three main families of CetZs, including CetZ1 and CetZ2 only present in Haloarchaea, where species typically possess multiple CetZ homologues, and non-Haloarchaea CetZs, which clustered separately from Haloarchaea CetZs and usually were the only CetZ encoded in each genome. Analysis of the 40 kb genomic regions surrounding the CetZ genes from these three families revealed that genes involved in cell envelope biogenesis, adhesion and motility, and purine and coenzyme biosynthesis are often associated with cetZs, suggesting that CetZs could contribute to a broad range of biological processes, and implicating them as important multifaceted cytoskeletal components in archaeal cell biology.

  1. Liao, Y.; Ithurbide, S.; Evenhuis, C.; Löwe, J.; Duggin, I.G. Cell division in the archaeon Haloferax volcanii relies on two FtsZ proteins with distinct functions in division ring assembly and constriction. Nature Microbiology 2021, 6, 594-605.
  2. Duggin, I.G.; Aylett, C.H.; Walsh, J.C.; Michie, K.A.; Wang, Q.; Turnbull, L.; Dawson, E.M.; Harry, E.J.; Whitchurch, C.B.; Amos, L.A. CetZ tubulin-like proteins control archaeal cell shape. Nature 2015, 519, 362.
  3. de Silva, R.T.; Abdul-Halim, M.F.; Pittrich, D.A.; Brown, H.J.; Pohlschroder, M.; Duggin, I.G. Improved growth and morphological plasticity of Haloferax volcanii. Microbiology (Reading) 2021, doi:10.1099/mic.0.001012.