SIRT6 Regulates Protein Synthesis and Folding Through Nucleolar Remodeling

Area of Science:

• Cellular Biology
• Neuroscience
• Aging Research

Background:

• Loss of proteostasis, crucial for cellular health, is a hallmark of aging and neurodegeneration.
• The precise mechanisms causing proteostasis loss remain incompletely understood.

Purpose of the Study:

• To investigate the role of SIRT6 in maintaining proteostasis.
• To elucidate the molecular mechanisms by which SIRT6 influences protein translation and cellular stress.

Main Methods:

• Investigated SIRT6's regulation of global translation, ribosomal genes, nucleolar function, and TIP5 chromatin localization.
• Utilized a C. elegans model (sir-2.4 knockout) to study in vivo effects on heat shock resistance and motility.
• Examined the impact of SIRT6 deficiency on proteostasis-stress intolerance and potential rescue by translation inhibitors.

Main Results:

• SIRT6 deletion led to increased nucleolar size, rRNA production, and global protein translation.
• Elevated translation exceeded chaperone capacity, resulting in reduced protein folding and aggregate production.
• In vivo, SIRT6 deficiency caused reduced heat shock resistance, accelerated motility decline, and premature death in a neurodegeneration model.

Conclusions:

• SIRT6 deficiency causes proteostasis loss primarily through nucleolar dysfunction and chromatin dysregulation.
• This loss of proteostasis contributes to age-dependent decline and neurodegeneration.
• Pharmacological reduction of protein translation can ameliorate SIRT6-deficiency-induced proteostasis defects.