Inhibition of Type 1 but not Type 2 mitophagy by 3-methyladenine. In (A), TMRM-loaded GFP-LC3 transgenic hepatocytes were incubated 120 min in serum-containing Waymouth׳s growth medium (left panel), KRG plus glucagon (KRH/G), or KRH/G plus 10 mM 3-methyladenine (3 MA), a PI3K inhibitor and classical autophagy blocker. In comparison to Waymouth׳s medium alone, incubation in KRH/G caused abundant formation of GFP-LC3-tagged autophagosomes, many of which contained TMRM-labeled polarized mitochondria (middle panel). 3 MA treatment prevented autophagosomal formation virtually completely (right panel). In (B), GFP-LC3 hepatocytes were subjected to 488-nm photoirradiation (circle), as described in , in the presence of 3 MA. Note that 3 MA did not prevent formation of mitophagosomes after photodamage (58 min, compare to ). Wortmannin (100 nM), another PI3K inhibitor, similarly failed to prevent mitophagosome formation after photodamage (not shown). Adapted from .