MAP1LC3 (shortened to LC3 in our antibody catalog) is one of four mammalian homologues of autophagy-related protein 8 (Atg8). It has been identified as a light chain subunit of the microtubule-associated proteins MAP1A/MAP1B. A modified form of LC3, LC3-II, has been identified as a marker for the autophagosomal membrane in mammals.
To date, LC3 is the only known reliable autophagosome marker. Three transcript variants (LC3A, B and C) have been identified in mammals, which undergo post-translational modification during autophagy. LC3 immunoblot assays generally reveal two bands: LC3-I, (the cytosolic form,) and LC3-II (the membrane-bound, lipidated form.)
During autophagy, LC3 is cleaved at the carboxy terminus immediately after synthesis, yielding the cytoplasmic LC3-I form. Following recruitment to the autophagosome, LC3-I is converted to LC3-II via a ubiquitin-like process of proteolysis and lipidation, involving Atg3 and Atg7. This allows LC3 to associate with the autophagic vesicles.
The LC3-II antibody is widely used to monitor autophagic activity in immunoblot and immunocytochemical assays. As the autophagosome is so short-lived, LC3-II dots represent an accurate method of recording autophagic activity at precise moments in time, with LC3-II levels correlating well with the number of autophagosomes.
We at Novus Biologicals have an extensive range of LC3 antibody products in our antibody catalog. These allow monitoring of endogenous LC3 levels; tracking of LC3-I to LC3-II conversion in real time, and analysis of LC3 cellular distribution. Our LC3 antibody products are widely used to study autophagic progression in tumourigenesis, cardiomyopathy, neurodegenerative disease and other pathological conditions.
