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  • NAD super(+) salvage pathwa...
    Ocampo, Alejandro; Liu, Jingjing; Barrientos, Antoni

    Human molecular genetics, 05/2013, Letnik: 22, Številka: 9
    Journal Article

    Increased levels of nicotinamide/nicotinic acid mononucleotide adenylyltransferase (NMNAT) act as a powerful suppressor of Wallerian degeneration and ataxin- and tau-induced neurodegeneration in flies and mice. However, the nature of the suppression mechanism/s remains controversial. Here, we show that in yeast models of proteinopathies, overexpression of the NMNAT yeast homologs, NMA1 and NMA2, suppresses polyglutamine (PolyQ) and alpha -synuclein-induced cytotoxicities. Unexpectedly, overexpression of other genes in the salvage pathway for NAD super(+) biosynthesis, including QNS1, NPT1 and PNC1 also protected against proteotoxicity. Our data revealed that in all cases, this mechanism involves extensive clearance of the non-native protein. Importantly, we demonstrate that suppression by NMA1 does not require the presence of a functional salvage pathway for NAD super(+) biosynthesis, SIR2 or an active mitochondrial oxidative phosphorylation (OXPHOS) system. Our results imply the existence of histone deacetylase- and OXPHOS-independent crosstalk between the proteins in the salvage pathway for NAD super(+) biosynthesis and the proteasome that can be manipulated to achieve cellular protection against proteotoxic stress.