Role of the mammalian ATG8/LC3 family in autophagy: differential and compensatory roles in the spatiotemporal regulation of autophagy

Abstract

Autophagy, an evolutionarily conserved cellular degradation pathway of the lysosome, is associated with many physiological and pathological processes. The hallmark of autophagy is the formation of the autophagosome that engulfs and degrades cytosolic components via its fusion with the lysosome, in either a selective or a non-selective manner. Autophagy is tightly regulated by proteins encoded by autophagy-related (atg) genes. Among these proteins, ATG8/LC3 is essential for autophagosome biogenesis/maturation and it also functions as an adaptor protein for selective autophagy. In mammalian cells, several homologs of yeast Atg8 such as MAP1LC3, GABARAP, and GABARAPL 1/2 have been identified. However, the biological relevance of this gene diversity in higher eukaryotes, and their specific roles, are largely unknown. In this review, we describe the mammalian ATG8/LC3 family and discuss recent advancements in understanding their roles in the autophagic process. [BMB Reports 2016; 49(8): 424-430]

Glioblastoma, hypoxia and autophagy: a survival-prone ‘ménage-à-trois’

“…63 The free form of the latter (LC3I) is transformed into the lipidated form LC3II by the covalent binding of a molecule of phosphatidyl ethanolamine. 64, 65 …”

Development of LC3/GABARAP sensors containing a LIR and a hydrophobic domain to monitor autophagy

“…ATG8/LC3/GABARAP proteins are the most widely used autophagosome markers. Eight human homologs comprise the microtubule‐associated protein 1 light chain (MAP1LC3) family (MAP1LC3A [LC3A], MAP1LC3B [LC3B], MAP1LC3B2 [LC3B2], and MAP1LC3C [LC3C], collectively referred to as “LC3”) and the γ‐aminobutyric acid (GABA) receptor‐associated proteins (GABARAP, GABARAPL1, GABARAPL2/GATE‐16, and GABARAPL3) (Wild et al , ; Lee & Lee, ). Although the specific functions of each isoform of mammalian LC3/GABARAP protein remain unknown, among these homologs, LC3B, an interacting partner of microtubule‐associated proteins 1A and 1B (MAP1A/1B), has been extensively studied and characterized as a component essential for autophagosome biogenesis.…”

Differences of basic and induced autophagic activity between K562 and K562/ADM cells

“…Macroautophagy, referred to autophagy hereinafter, exerts its function through formation of autophagosomes and subsequently being fused with lysosomes, triggering substances being degraded by acid hydrolases. Consequently, the catabolites including amino acids, fatty acids, nucleotides and so on are recycled in cytoplasm to reenter biological energy pathways, ultimately maintaining structure and metabolism of cells (6).…”