The bio3d package is distributed with full source code as a platform-independent R package under a GPL2 license from: http://mccammon.ucsd.edu/~bgrant/bio3d/

Organisms that protect their germ-cell lineages from damage often do so at considerable cost: limited metabolic resources become partitioned away from maintenance of the soma, leaving the ageing somatic tissues to navigate survival amid an environment containing damaged and poorly functioning proteins. Historically, experimental paradigms that limit reproductive investment result in lifespan extension. We proposed that germline-deficient animals might exhibit heightened protection from proteotoxic stressors in somatic tissues. We find that the forced re-investment of resources from the germ line to the soma in Caenorhabditis elegans results in elevated somatic proteasome activity, clearance of damaged proteins and increased longevity. This activity is associated with increased expression of rpn-6, a subunit of the 19S proteasome, by the FOXO transcription factor DAF-16. Ectopic expression of rpn-6 is sufficient to confer proteotoxic stress resistance and extend lifespan, indicating that rpn-6 is a candidate to correct deficiencies in age-related protein homeostasis disorders.

Activating AMPK or inactivating calcineurin slows ageing in Caenorhabditis elegans1,2 and both have been implicated as therapeutic targets for age-related pathology in mammals3–5. However, the direct targets that mediate their effects on longevity remain unclear. In mammals, CREB-regulated transcriptional coactivators (CRTCs)6 are a family of cofactors involved in diverse physiological processes including energy homeostasis7–9, cancer10 and endoplasmic reticulum stress11. Here we show that both AMPK and calcineurin modulate longevity exclusively through post-translational modification of CRTC-1, the sole C. elegans CRTC. We demonstrate that CRTC-1 is a direct AMPK target, and interacts with the CREB homologue-1 (CRH-1) transcription factor in vivo. The pro-longevity effects of activating AMPK or deactivating calcineurin decrease CRTC-1 and CRH-1 activity and induce transcriptional responses similar to those of CRH-1 null worms. Downregulation of crtc-1 increases lifespan in a crh-1-dependent manner and directly reducing crh-1 expression increases longevity, substantiating a role for CRTCs and CREB in ageing. Together, these findings indicate a novel role for CRTCs and CREB in determining lifespan downstream of AMPK and calcineurin, and illustrate the molecular mechanisms by which an evolutionarily conserved pathway responds to low energy to increase longevity.

Chemical modulation of histone deacetylase (HDAC) activity by HDAC inhibitors (HDACi) is an increasingly important approach to modify the etiology of human disease. Loss-of-function diseases arise as a consequence of protein misfolding and degradation leading to system failures. The ΔF508 mutation in cystic fibrosis transmembrane conductance regulator (CFTR) results in the absence of the cell surface chloride channel and a loss of airway hydration, leading to premature lung failure and reduced lifespan responsible for cystic fibrosis (CF). We now show that the HDACi suberoylanilide hydroxamic acid (SAHA) restores surface channel activity in human primary airway epithelia to levels that are 28% of wild-type CFTR. Biological silencing of all known class I and II HDACs reveals that HDAC7 plays a central role in restoration of ΔF508 function. We suggest that the tunable capacity of HDACs can be manipulated by chemical biology to counter the onset of CF and other human misfolding disorders.