Eukaryotic-like gephyrin and cognate membrane receptor coordinate corynebacterial cell division and polar elongation.

The order Corynebacteriales includes major industrial and pathogenic actinobacteria such as Corynebacterium glutamicum or Mycobacterium tuberculosis . Their elaborate multi-layered cell wall, composed primarily of the mycolyl-arabinogalactan-peptidoglycan complex, and their polar growth mode impose a stringent coordination between the septal divisome, organized around the tubulin-like protein FtsZ, and the polar elongasome, assembled around the tropomyosin-like protein Wag31. Here, we report the identification of two new divisome members, a gephyrin-like repurposed molybdotransferase (GLP) and its membrane receptor (GLPR). We show that the interplay between the GLPR/GLP module, FtsZ and Wag31 is crucial for orchestrating cell cycle progression. Our results provide a detailed molecular understanding of the crosstalk between two essential machineries, the divisome and elongasome, and reveal that Corynebacteriales have evolved a protein scaffold to control cell division and morphogenesis similar to the gephyrin/GlyR system that in higher eukaryotes mediates synaptic signaling through network organization of membrane receptors and the microtubule cytoskeleton.

Proteomic identification of M. tuberculosis protein kinase substrates: PknB recruits GarA, a FHA domain-containing protein, through activation loop-mediated interactions.

Genes for functional Ser/Thr protein kinases (STPKs) are ubiquitous in prokaryotic genomes, but little is known about their physiological substrates and their actual involvement in bacterial signal transduction pathways. We report here the identification of GarA (Rv1827), a Forkhead-associated (FHA) domain-containing protein, as a putative physiological substrate of PknB, an essential Ser/Thr protein kinase from Mycobacterium tuberculosis. Using a global proteomic approach, GarA was found to be the best detectable substrate of the PknB catalytic domain in non-denatured whole-cell protein extracts from M. tuberculosis and the saprophyte Mycobacterium smegmatis. Enzymological and binding studies of the recombinant proteins demonstrate that docking interactions between the activation loop of PknB and the C-terminal FHA domain of GarA are required to enable efficient phosphorylation at a single N-terminal threonine residue, Thr22, of the substrate. The predicted amino acid sequence of the garA gene, including both the N-terminal phosphorylation motif and the FHA domain, is strongly conserved in mycobacteria and other related actinomycetes, suggesting a functional role of GarA in putative STPK-mediated signal transduction pathways. The ensuing model of PknB-GarA interactions suggests a substrate recruitment mechanism that might apply to other mycobacterial kinases bearing multiple phosphorylation sites in their activation loops.

Cervical screening in Luxembourg: 1990-1999.

For quality assurance purposes, the results of the 1990's obtained by the National Cervical Cancer Screening Programme (NCCSP) launched in 1962 were reviewed. The positive cytodiagnosis, the histologically verified in situ and invasive cervical cancers and the mortality rates were reported.

Cervical cancer screening in Luxembourg.

In 1962, a programme for early detection of cervical cancer was established at the national level. The programme is based on the collaboration of different groups of doctors and not on a system of sending out invitations to every woman. This programme was re-adapted twice according to the needs for assuring quality in a system of mainly liberal medicine. At present the programme is 'institutionalised' and is carried out according to the criteria defined in 1990. This includes a centralisation of the smear readings and handing out the material needed to take the smears. The contribution of the doctors is regulated by a system of bonuses given by the government and a reimbursement by the Health Fund. The annual cervical smear is free of charge for every woman. The participation of the women targeted by the programme (>15 years old) has increased by approximately 50% every decade from the early 1970s increasing from 10950 in 1972 to 70441 in 1999. Between 1980 and 1999, the number of women at risk taking part in the programme increased from 10.80 to 38.92%. The number of all the doctors taking smear samples increased from 68 to 105 and the number of gynaecologists increased from 19 (ratio Gyn/GP (gynaecologists/General Practitioners) of 28%) to 52 (ratio Gyn/GP of 50%). The mortality rate has decreased continuously from 6. 1/100000 in 1990 to 0.9/100000 in 1997. In conclusion, to be successful, a cervical cancer screening programme should be flexible enough to allow short-term adaptations to unexpected local situations and needs a highly motivated team of the different participants involved in the regional and national health policy.