AKT Phosphorylates FAM13A and Promotes Its Degradation via CUL4A/DDB1/DCAF1 E3 Complex

Area of Science:

• Molecular Biology
• Cellular Biology
• Pulmonary Medicine

Background:

• Single nucleotide polymorphisms (SNPs) in the FAM13A gene are linked to chronic obstructive pulmonary disease (COPD) and lung function.
• The regulation of FAM13A protein under physiological and pathological conditions is not well understood.

Purpose of the Study:

• To elucidate the regulatory mechanisms governing FAM13A protein stability.
• To investigate the functional role of FAM13A regulation in lung epithelial repair.

Main Methods:

• Treatment of cells with cigarette smoke extract.
• Analysis of FAM13A phosphorylation and ubiquitination.
• In vivo studies using mouse models of lung injury (influenza, naphthalene).
• Assessment of epithelial cell proliferation during lung repair.

Main Results:

• FAM13A is phosphorylated at serine 312 by AKT kinase upon cigarette smoke extract treatment.
• Phosphorylated FAM13A is recognized and degraded by the CULLIN4A/DCAF1 E3 ligase complex.
• FAM13A protein is downregulated upon AKT activation in stressed and injured mouse lungs.
• Reduced FAM13A levels promote accelerated lung epithelial cell proliferation during repair.

Conclusions:

• A novel mechanism for FAM13A protein regulation via ubiquitination-mediated degradation has been characterized.
• This regulatory pathway fine-tunes lung epithelial repair following injury.
• Understanding FAM13A regulation may offer insights into COPD and other lung diseases.