ATG5 is a protein encoded by the ATG5 gene in humans. The recombinant form of ATG5 is typically produced in E. coli and is a single, non-glycosylated polypeptide chain containing 295 amino acids, with a molecular mass of approximately 34.6 kDa . The recombinant protein often includes a His-tag at the N-terminus to facilitate purification .
ATG5 is indispensable in both canonical and non-canonical autophagy pathways . It plays a pivotal role in the formation of the autophagosome, a double-membrane vesicle that engulfs cellular components for degradation. The process begins with the elongation of the phagophore, a precursor to the autophagosome. ATG5 interacts with the ubiquitin-like protein ATG12 to form the ATG12-ATG5 conjugate, a critical step in autophagosome formation .
The formation of the ATG12-ATG5 conjugate is dependent on the activities of ATG7 (an E1-like enzyme) and ATG10 (an E2-like enzyme). This conjugate then interacts non-covalently with ATG16L1, forming a large complex that associates with the nascent phagophore . Once the autophagosome is fully formed, the ATG16L1 complex dissociates.
ATG5 is involved in various physiological processes, including cellular differentiation, development, and immune responses . It also plays a role in the degradation of intracellular pathogens and the regulation of inflammation. Dysregulation of autophagy and ATG5 has been implicated in numerous diseases, including cancer, neurodegenerative disorders, and autoimmune diseases .
Recent studies have highlighted the role of ATG5 in modulating the immune system and its crosstalk with apoptosis. Understanding the regulatory mechanisms of ATG5 in autophagy can provide insights into the pathogenesis of various immune-related diseases and potentially lead to new therapeutic strategies .
Recombinant human ATG5 is widely used in research to study the autophagy process and its implications in health and disease. It serves as a valuable tool for investigating the molecular mechanisms underlying autophagy and for developing potential therapeutic interventions targeting autophagy-related pathways .