Figure 1. Physiological functions of the histone chaperone homologs LIN-53 and RBBP4/7 with respect to cellular safeguarding, muscular healthspan, and aging. In C. elegans the histone chaperone LIN-53 functions through the histone deacetylase complex Sin3 to ensure normal lifespan, while its function via the chromatin remodelling complex NuRD is required for muscle maintenance during aging. RBBP4/7 are the human homologs of LIN-53 and act through NuRD to prevent premature aging as seen in patients with the laminopathy disease Progeria. It remains to be determined whether RBBP4/7 are also required for muscle healthspan to prevent muscle decay in laminopathies with known muscle phenotypes. LIN-53 and its homologs safeguard cell fates by acting as reprogramming barriers via the PRC2 complex in C. elegans and CAF1 complex in mouse fibroblasts.