Binding of the Atg1/ULK1 kinase to the ubiquitin-like protein Atg8 regulates autophagy.

Autophagy is an intracellular trafficking pathway sequestering cytoplasm and delivering excess and damaged cargo to the vacuole for degradation. The Atg1/ULK1 kinase is an essential component of the core autophagy machinery possibly activated by binding to Atg13 upon starvation. Indeed, we found that Atg13 directly binds Atg1, and specific Atg13 mutations abolishing this interaction interfere with Atg1 function in vivo. Surprisingly, Atg13 binding to Atg1 is constitutive and not altered by nutrient conditions or treatment with the Target of rapamycin complex 1 (TORC1)-inhibitor rapamycin. We identify Atg8 as a novel regulator of Atg1/ULK1, which directly binds Atg1/ULK1 in a LC3-interaction region (LIR)-dependent manner. Molecular analysis revealed that Atg13 and Atg8 cooperate at different steps to regulate Atg1 function. Atg8 targets Atg1/ULK1 to autophagosomes, where it may promote autophagosome maturation and/or fusion with vacuoles/lysosomes. Moreover, Atg8 binding triggers vacuolar degradation of the Atg1-Atg13 complex in yeast, thereby coupling Atg1 activity to autophagic flux. Together, these findings define a conserved step in autophagy regulation in yeast and mammals and expand the known functions of LIR-dependent Atg8 targets to include spatial regulation of the Atg1/ULK1 kinase.

An HIV1/2 point of care test on sputum for screening TB/HIV co-infection in Central India - Will it work?

OBJECTIVE: To determine whether the OraQuick® HIV-1/2 Assay (OraSure Technologies, Inc., Bethlehem, PA, USA) in sputum is a valid tool for HIV surveillance among TB patients. METHODS: A cross sectional study was carried out on sputa of patients diagnosed with tuberculosis. Sputa were tested for antibodies to HIV using OraQuick® HIV-1/2 Assay (OraSure Technologies, Inc., Bethlehem, PA, USA). The results were compared with results of serum ELISA. RESULTS: Compared to serum ELISA, the OraQuick® HIV-1/2 Assay in sputum specimens reported 90% sensitivity (9/10) and 100% specificity (307/307), with a positive predictive value of 100% (95%CI: 66.37%-100.00%) and a negative predictive value of 99.68% (95%CI: 98.20%-99.99%). CONCLUSIONS: This testing method may provide a useful strategy for conducting HIV surveillance in possible co-infected TB patients at peripheral centres. Since there is no investment on infrastructure, it may be possible for paramedical health professionals to carry out the test, particularly in areas with low HIV endemicity.

Isolated ulcerative skin lesion caused by Salmonella Weltevreden.

Salmonella enterica serovar Weltevreden is not a commonly isolated serotype in India. We report isolation of Salmonella Weltevreden, from an unusual site--an ulcer on the gluteal region of a patient who had undergone coronary artery bypass surgery. To our knowledge, Salmonellae have never been reported to cause isolated ulcerative lesions on the skin. This is the first report of an isolated ulcerative lesion on the skin caused by Salmonella Weltevreden. Our findings indicate that there may be modes of pathogenesis of Salmonella infections that we are yet unaware of. Further work and extensive reporting of all Salmonella infections are necessary to elucidate these mechanisms.