Reduction of Cullin-2 in somatic cells disrupts differentiation of germline stem cells in the Drosophila ovary.

Signaling from a niche consisting of somatic cells is essential for maintenance of germline stem cells (GSCs) in the ovary of Drosophila. Decapentaplegic (Dpp), a type of bone morphogenetic protein (BMP) signal, emanating from the niche, is the most important signal for this process. Cullin proteins constitute the core of a multiprotein E3-ligase important for their functions viz.

SIRT4 regulates ATP homeostasis and mediates a retrograde signaling via AMPK.

Efficient coupling of cellular energy production to metabolic demand is crucial to maintain organismal homeostasis. Here, we report that the mitochondrial Sirtuin Sirt4 regulates mitochondrial ATP homeostasis. We find that Sirt4 affects mitochondrial uncoupling via the adenine nucleotide translocator 2 (ANT2).

dSir2 in the adult fat body, but not in muscles, regulates life span in a diet-dependent manner.

Sir2, an evolutionarily conserved NAD(+)-dependent deacetylase, has been implicated as a key factor in mediating organismal life span. However, recent contradictory findings have brought into question the role of Sir2 and its orthologs in regulating organismal longevity. In this study, we report that Drosophila Sir2 (dSir2) in the adult fat body regulates longevity in a diet-dependent manner.

Small changes, big effects: chromatin goes aging.

Aging is a complex trait and is influenced by multiple factors that are both intrinsic and extrinsic to the organism (Kirkwood et al. 2000; Knight 2000). Efforts to understanding the mechanisms that extend or shorten lifespan have been made since the early twentieth century.

dSir2 deficiency in the fatbody, but not muscles, affects systemic insulin signaling, fat mobilization and starvation survival in flies.

Sir2 is an evolutionarily conserved NAD+ dependent protein. Although, SIRT1 has been implicated to be a key regulator of fat and glucose metabolism in mammals, the role of Sir2 in regulating organismal physiology, in invertebrates, is unclear. Drosophila has been used to study evolutionarily conserved nutrient sensing mechanisms, however, the molecular and metabolic pathways downstream to Sir2 (dSir2) are poorly understood.