RESUMO
Cells under mitochondrial stress often co-opt mechanisms to maintain energy homeostasis, mitochondrial quality control and cell survival. A mechanistic understanding of such responses is crucial for further insight into mitochondrial biology and diseases. Through an unbiased genetic screen in Drosophila, we identify that mutations in lrpprc2, a homolog of the human LRPPRC gene that is linked to the French-Canadian Leigh syndrome, result in PINK1-Park activation. While the PINK1-Park pathway is well known to induce mitophagy, we show that PINK1-Park regulates mitochondrial dynamics by inducing the degradation of the mitochondrial fusion protein Mitofusin/Marf in lrpprc2 mutants. In our genetic screen, we also discover that Bendless, a K63-linked E2 conjugase, is a regulator of Marf, as loss of bendless results in increased Marf levels. We show that Bendless is required for PINK1 stability, and subsequently for PINK1-Park mediated Marf degradation under physiological conditions, and in response to mitochondrial stress as seen in lrpprc2. Additionally, we show that loss of bendless in lrpprc2 mutant eyes results in photoreceptor degeneration, indicating a neuroprotective role for Bendless-PINK1-Park mediated Marf degradation. Based on our observations, we propose that certain forms of mitochondrial stress activate Bendless-PINK1-Park to limit mitochondrial fusion, which is a cell-protective response.
Assuntos
Proteínas de Drosophila , Proteínas Quinases , Animais , Humanos , Proteínas Quinases/genética , Proteínas Quinases/metabolismo , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Ubiquitina-Proteína Ligases/genética , Canadá , Mitocôndrias/genética , Mitocôndrias/metabolismo , Drosophila/genética , Drosophila/metabolismo , Proteínas Mitocondriais/genética , Proteínas Mitocondriais/metabolismo , Proteínas de Neoplasias/metabolismo , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/metabolismoRESUMO
In India approximately 1 million people get burnt every year and most of them are from the lower or middle income strata. Therefore it is obligatory to find out an economic way of treatment for the affected populace. Since use of human skin allograft is the gold standard for the treatment of burn wound, in-house skin banking for a burn unit hospital is prerequisite to make the treatment procedure affordable. Although, there was one skin bank at India till 2009, but it was difficult for a single bank to cover the entire country's need. Looking at the necessities, National Burns Centre (a tertiary burn care centre) along with Rotary International and Euro Skin Bank collaborated and developed an effective cadaveric skin banking model in Mumbai, Maharashtra in 2009. Initial two to three years were formation phase; by the year 2013 the entire system was organized and started running full fledged. The model has also been replicated in other states of India to accommodate the large burn population of the country. This paper therefore, gives a step by step account of how the bank evolved and its present status.