What intracellular proteins does lithium inhibit?

Lithium inhibits intracellular proteins such as PKC, IMPase, GSK-3, IPPase, and MARCKS. It has been hypothesized that lithium induces mood-stabilizing effects through inhibiting IMPase. It decreases inositol concentration and the quantity of PIP2 for signaling cascades which are dependent on this pathway (e.g. receptor tyrosine kinase pathways, neurotrophin signaling pathways). Lithium also directly inhibits GSK3 by disarranging the network of the AKT; βArr2;PP2A signaling complex and increasing Akt activity. It also inhibits GSK-3 through competition for magnesium, as it binds specifically to the ATP-dependent magnesium sensitive catalytic site of the enzyme. Lithium inhibits IMPase and IPPase which leads to subsequent depletion of inositol and downstream targets of the cycle (IP3). This causes a decrease in release of calcium, and diacylglycerol activation. The inhibition of MARCKS by lithium has been suggested to be related to activity of PKC. This is because MARKS dissociates from the membrane and moves to the cytoplasm following phosphorylation by PKC.