DipM controls multiple autolysins and mediates a regulatory feedback loop promoting cell constriction in Caulobacter crescentus.

Proteins with a catalytically inactive LytM-type endopeptidase domain are important regulators of cell wall-degrading enzymes in bacteria. Here, we study their representative DipM, a factor promoting cell division in Caulobacter crescentus. We show that the LytM domain of DipM interacts with multiple autolysins, including the soluble lytic transglycosylases SdpA and SdpB, the amidase AmiC and the putative carboxypeptidase CrbA, and stimulates the activities of SdpA and AmiC. Its crystal structure reveals a conserved groove, which is predicted to represent the docking site for autolysins by modeling studies. Mutations in this groove indeed abolish the function of DipM in vivo and its interaction with AmiC and SdpA in vitro. Notably, DipM and its targets SdpA and SdpB stimulate each other's recruitment to midcell, establishing a self-reinforcing cycle that gradually increases autolytic activity as cytokinesis progresses. DipM thus coordinates different peptidoglycan-remodeling pathways to ensure proper cell constriction and daughter cell separation.

Interacting bactofilins impact cell shape of the MreB-less multicellular Rhodomicrobium vannielii.

Most non-spherical bacteria rely on the actin-like MreB cytoskeleton to control synthesis of a cell-shaping and primarily rod-like cell wall. Diverging from simple rod shape generally requires accessory cytoskeletal elements, which locally interfere with the MreB-guided cell wall synthesis. Conserved and widespread representatives of this accessory cytoskeleton are bactofilins that polymerize into static, non-polar bundles of filaments. Intriguingly, many species of the Actinobacteria and Rhizobiales manage to grow rod-like without MreB by tip extension, yet some of them still possess bactofilin genes, whose function in cell morphogenesis is unknown. An intricate representative of these tip-growing bacteria is Rhodomicrobium vannielii; a member of the hitherto genetically not tractable and poorly studied Hyphomicrobiaceae within the MreB-less Rhizobiales order. R. vannielii displays complex asymmetric cell shapes and differentiation patterns including filamentous hyphae to produce offspring and to build dendritic multicellular arrays. Here, we introduce techniques to genetically access R. vannielii, and we elucidate the role of bactofilins in its sophisticated morphogenesis. By targeted mutagenesis and fluorescence microscopy, protein interaction studies and peptidoglycan incorporation analysis we show that the R. vannielii bactofilins are associated with the hyphal growth zones and that one of them is essential to form proper hyphae. Another paralog is suggested to represent a novel hybrid and co-polymerizing bactofilin. Notably, we present R. vannielii as a powerful new model to understand prokaryotic cell development and control of multipolar cell growth in the absence of the conserved cytoskeletal element, MreB.

Digitalization and disruptive change in rheumatology.

INTRODUCTION: Recently, many sectors have seen disruptive changes due to the rapid progress in information and communication technology (ICT). The aim of this systematic literature review was to develop a first understanding of what is known about new ICTs in rheumatology and their disruptive potential. METHODS: PubMed, LIVIVO, and EBSCO Discovery Service (EDS) databases were searched for relevant literature. Use of new ICTs was identified, categorized, and disruptive potential was discussed. Articles from 2008 to 2021 in German and English were considered. RESULTS: A total of 3539 articles were identified. After application of inclusion/exclusion criteria, 55 articles were included in the analyses. The majority of articles (48) used a non-experimental design or detailed expert opinion. The new ICTs mentioned in these articles could be allocated to four main categories: technologies that prepare for the development of new knowledge by data collection (n = 32); technologies that develop new knowledge by evaluation of data (e.g., by inventing better treatment; n = 11); technologies that improve communication of existing knowledge (n = 32); and technologies that improve the care process (n = 29). Further assessment classified the ICTs into different functional subcategories. Based on these categories it is possible to estimate the disruptive potential of new ICTs. CONCLUSION: ICTs are becoming increasingly important in rheumatology and may impact patients' lives and professional conduct. The properties and disruptive potential of technologies identified in the articles differ widely. When looking into ICTs, doctors have focused on new diagnostic and therapeutic procedures but rarely on their disruptive potential. We recommend putting more effort into investigation of whether ICTs change the way rheumatology is performed and who is in control of it. Especially technologies that potentially replace physicians with machines, take control over the definition of quality in medicine, and/or create proprietary knowledge that is not accessible for doctors need more research.