Almost all Sulfolobales contain an type IV pili operon named the UV inducible pilus operon (ups). This operon is highly induced after UV treatment of Sulfolobus cells or the occurence of DNA double strand breakages. As a result the cells express multiple pili all around the cell surface and start to aggregate (see image). In these aggregates the cells exchange DNA which is subsequently used to repair their genomic DNA by homologous recombination.
Recently, we have have identified the DNA importer, the Ced system (Crenarchaeal exchange of DNA), which takes up the DNA during the aggregation process and is depending on an ATPase (Van Wolferen et al., PNAS, 2016). We are now trying to understand how the cells aggregate and how the cell-cell-connection is established.
Recently we have shown that the cells interact species-specific. The species specificity is determined by the UpsA pilin component which interacts specifically with the N-glycan on the surface of the S-layer protein (van Wolferen et al., mBio. 2020).
van Wolferen M, Wagner A, van der Does C, Albers SV. (2016) The archaeal Ced system imports DNA
Proc Natl Acad Sci U S A. 2016 Mar 1;113(9):2496-501. doi: 10.1073/pnas.1513740113.
van Wolferen M, Ajon M, Driessen AJ, Albers SV. (2013) Molecular analysis of the UV-inducible pili operon from Sulfolobus acidocaldarius.
Microbiologyopen. 2013 Dec;2(6):928-37. doi: 10.1002/mbo3.128. Epub 2013 Sep 19.
Ajon M, Fröls S, van Wolferen M, Stoecker K, Teichmann D, Driessen AJ, Grogan DW, Albers SV, Schleper C. (2011) UV-inducible DNA exchange in hyperthermophilic archaea mediated by type IV pili. Mol Microbiol. 82(4):807-17. doi: 10.1111/j.1365-2958.2011.07861.x