Dynamics of the Synechococcus elongatus cytoskeletal GTPase FtsZ yields mechanistic and evolutionary insight into cyanobacterial and chloroplast FtsZs

Differential GTP-dependentin-vitropolymerization of recombinant Physcomitrella FtsZ proteins

“…Our results support the idea (Porter et al, 2023) that a low GTPase activity of plant FtsZ proteins compared to bacterial FtsZ is a conserved feature. One reason might be that bacteria divide faster than chloroplasts, and thus require a higher GTPase activity and faster assembly of the Z-ring.…”

“…Based on the mutant phenotypes (Martin et al, 2009b, Özdemir et al, 2018) the localization of Physcomitrella FtsZ in E. coli (this study), the in vivo (Özdemir et al, 2018 and this study) and our in-vitro studies, we postulate different roles for FtsZ1-2 and FtsZ2-1 regarding the assembly of the plastoskeleton. Physcomitrella FtsZ2-1 might be more involved in chloroplast division and shaping, which, taken together with its lower GTPase activity, supports the idea (Porter et al, 2023) that the low GTPase activity of chloroplast FtsZ proteins compared to bacterial FtsZ is a conserved feature. FtsZ1-2 on the other hand might be more involved in chloroplast-chloroplast interaction via highly dynamic stromule formation, which needs longer filaments and a higher GTPase activity.…”

“…Upon addition of GTP, an increase in light scattering was observed in the presence of 15 µM FtsZ1-2, suggesting that this isoform is capable of forming filaments in the presence of GTP. The increase was notable but relatively slow when compared to other plant FtsZ proteins at similar concentrations (Porter et al, 2021;Porter et al, 2023). Remarkably, no increase in light scattering could be observed when the experiment was performed with buffer containing NaCl, once again suggesting that NaCl inhibits polymerization of FtsZ1-2.…”

“…The foci at higher FtsZ concentration could represent FtsZ nucleation sites, as suggested by Ma et al (1996). In contrast, Synechococcus elongatus FtsZ tagged with mCerulean and Arabidopsis FtsZ1 tagged with mVenus localize to long curved filaments when expressed separately in yeast (Porter et al, 2023). The localization of Physcomitrella FtsZ1-2 and FtsZ2-1 in E. coli indicates that the FtsZ function is evolutionary conserved and that Physcomitrella FtsZ interferes with cell division and morphology when overexpressed in E. coli .…”

“…Furthermore, we investigated the interaction of these isoforms in vivo, and visualised both FtsZ isoforms in E. coli cells individually and in combination without potential interaction partners. Different bacterial FtsZ (e.g., B. subtilis FtsZ and E. coli FtsZ, Król & Scheffers, 2013;Agrobacterium tumefaciens FtsZ, Howell et al, 2019;Synechococcus elongatus, Porter et al, 2023), archaeal FtsZ (Haloferax volcanii;Liao et al, 2021;Ithurbide et al, 2022), and plant FtsZ (Arabidopsis, Porter et al, 2021;Porter et al, 2023) were already investigated regarding their assembly and biochemical properties. Here, we provide insights into the GTP-dependent polymerization and the assembly properties of FtsZ1-2 and FtsZ2-1 of the moss Physcomitrella.…”