Figure 2. Intracellular PI3P pools and PI3P phosphatases in autophagy regulation.

MTMR14 and MTMR3 inhibit autophagy by dephosphorylating PI3P involved in autophagosome formation. MTMR6 and MTMR7 depletions increase LC3-II via unknown mechanisms. Since MTMR6 regulates KCa3.1, we propose that MTMR6 might modulate autophagy by acting on Ca²⁺ influx. We speculate that some PI3P phosphatases might regulate autophagy by dephosphorylating pools of PI3P and/or PI3,5P₂ involved in Akt and mTOR activation (a and b), autolysosome formation/membrane recycling (c) and autophagosome transport (d) (see text and (52)). AP: autophagosome; AL: autolysosome. a.a.:amino-acids. In red: PI3P phosphatases inhibiting autophagy. IM: isolation membrane; In bold: PI3P phosphatases whose knockdown affect LC3-II level. Question marks indicate that the role of these pathways in regulating autophagy is speculative and remains to be investigated.