The LonB protease modulates the degradation of CetZ1 involved in rod-shape determination in Haloferax volcanii

Abstract

The function and natural targets of the archaeal membrane-associated LonB protease are mostly unknown. In this study, pull down assays combined with MS analysis were performed in Haloferax volcanii cells containing different LonB concentrations to identify LonB-interacting proteins. From a total of 281 proteins identified, ninety (90) co-immunoprecipitated specifically with LonB and were considered as Lon-interacting proteins. Interestingly, this approach evidenced that several tubulin homologues have a link with LonB, including the rod-shape determinant protein CetZ1 and the divisome component FtsZ1. This finding complements previous proteomics data obtained by our group. In vivo assays showed that modulation of LonB expression impacts on the degradation of CetZ1, which may account for the atypical irregular-elongated cell shape of H. volcanii mutant cells containing reduced LonB concentrations. The potential link between LonB and cell division is discussed.