Figure 6. Working model of the size, stoichiometry, and organization of cytoplasmic LC3B-associated complexes. On average one soluble Venus-LC3B is constitutively bound to an approximately 500 kDa complex of unknown composition. Mutating LC3B residue R70 to an alanine disrupts LC3B’s association with the large complex. Mutating LC3B residues F52 and L53 to alanines results in altered stoichiometry and binding to a second, ~50 MDa, complex. Mutating LC3B residue G120 to an alanine does not change its effective size or stoichiometry.