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. Author manuscript; available in PMC: 2014 Jul 1.
Published in final edited form as: Biochim Biophys Acta. 2012 Nov 9;1832(7):972–978. doi: 10.1016/j.bbadis.2012.11.001

Figure 3.

Figure 3

mTORC-independent regulation of autophagy

Inositol 1,4,5-triphosphate (IP3) mediates mTORC-independent regulation of autophagy. IP3 binding to the endoplasmic reticulum (ER) instigates the release of calcium into the cytoplasm. Binding of agonists to L-type calcium channels also increases the cytoplasmic levels of calcium. The increase in cytoplasmic calcium induces the activation of a family of calcium-dependent cysteine proteases called calpains. Activated calpains cleave and activate Gsα, which induces adenylyl cyclase activity to increase the concentration of cAMP. Elevated cAMP activates the Epac molecule, which activates phospholipase C (PLC)-ε and increases IP3, thereby completing this regulatory loop.