Phosphorylation of p125FAK and paxillin focal adhesion proteins in src-transformed cells with different metastatic capacity

AbstractHamster fibroblasts transformed by Rous sarcoma virus (RSV) display different metastatic potentials that are associated with specific structural features of the v-src oncoprotein. This diverse metastatic activity could be due to various tyrosine phosphorylation levels of specific src protein substrates. To check this hypothesis, phosphorylation of the FAK and paxillin proteins, involved in signal transduction pathways and known as src protein substrates, was tested. It was shown that FAK and paxillin are hyperphosphorylated in the high metastatic cell lines as compared with the phosphotyrosine level of these proteins found in the low metastatic cell lines. In addition, our data confirm that v-src protein plays a direct role in paxillin phosphorylation

Characterisation of porin genes from Mycobacterium fortuitum and their impact on growth

<p>Abstract</p> <p>Background</p> <p>Highly pathogenic mycobacteria like <it>Mycobacterium tuberculosis </it>are characterised by their slow growth and their ability to reside and multiply in the very hostile phagosomal environment and a correlation between the growth rate of mycobacteria and their pathogenicity has been hypothesised. Here, porin genes from <it>M. fortuitum </it>were cloned and characterised to address their impact on the growth rate of fast-growing and pathogenic mycobacteria.</p> <p>Results</p> <p>Two genes encoding porins orthologous to MspA from <it>M. smegmatis, porM1 </it>and <it>porM2</it>, were cloned from <it>M. fortuitum </it>strains, which were originally isolated from human patients. Both porin genes were at least partially able to complement the mutations of a <it>M. smegmatis </it>mutant strain lacking the genes <it>mspA </it>and <it>mspC </it>with respect to the growth rate. <it>PorM1 </it>and <it>porM2 </it>were present in different strains of <it>M. fortuitum </it>including the type strain. Comparative expression analysis of <it>porM </it>genes revealed divergent porin expression among analysed <it>M. fortuitum </it>strains. Repression of the expression of porins by antisense technique decreased the growth rates of different <it>M. fortuitum</it>. The effects of over-expression of <it>porM1 </it>as well as <it>porM2 </it>varied depending on the strain and the concentration of antibiotic added to the medium and indicated that PorM1 and PorM2 enhance the growth of <it>M. fortuitum </it>strains, but also the diffusion of the antibiotic kanamycin into the cells.</p> <p>Conclusion</p> <p>This study demonstrates the important role of porin expression in growth as well as antibiotic susceptibility of the opportunistic bacterium <it>M. fortuitum</it>.</p

The Complete Genome Sequence of Thermoproteus tenax: A Physiologically Versatile Member of the Crenarchaeota

Here, we report on the complete genome sequence of the hyperthermophilic Crenarchaeum Thermoproteus tenax (strain Kra 1, DSM 2078(T)) a type strain of the crenarchaeotal order Thermoproteales. Its circular 1.84-megabase genome harbors no extrachromosomal elements and 2,051 open reading frames are identified, covering 90.6% of the complete sequence, which represents a high coding density. Derived from the gene content, T. tenax is a representative member of the Crenarchaeota. The organism is strictly anaerobic and sulfur-dependent with optimal growth at 86 degrees C and pH 5.6. One particular feature is the great metabolic versatility, which is not accompanied by a distinct increase of genome size or information density as compared to other Crenarchaeota. T. tenax is able to grow chemolithoautotrophically (CO2/H-2) as well as chemoorganoheterotrophically in presence of various organic substrates. All pathways for synthesizing the 20 proteinogenic amino acids are present. In addition, two presumably complete gene sets for NADH:quinone oxidoreductase (complex I) were identified in the genome and there is evidence that either NADH or reduced ferredoxin might serve as electron donor. Beside the typical archaeal A(0)A(1)-ATP synthase, a membrane-bound pyrophosphatase is found, which might contribute to energy conservation. Surprisingly, all genes required for dissimilatory sulfate reduction are present, which is confirmed by growth experiments. Mentionable is furthermore, the presence of two proteins (ParA family ATPase, actin-like protein) that might be involved in cell division in Thermoproteales, where the ESCRT system is absent, and of genes involved in genetic competence (DprA, ComF) that is so far unique within Archaea