SIRT4 and lung cancer: A recent study shows that in lung cancer cells, sirtuin 4 (SIRT4, an nicotinamide-adenine dinucleotide+ (NAD+)-dependent protein deacetylase) inhibits Drp1 phosphorylation at the S616 site and weakens Drp1 recruitment to the mitochondrial membrane via an interaction with Fis1 (122).