Figure 1

The binding between apoA-I and ABCA1 effects signal transduction pathways. (A) ApoA-I binding to ABCA1 which couples to Gα_s leading to activation of AC, cAMP production and subsequent PKA-mediated ABCA1 phosphorylation, allowing lipidation of apoA-I. (B) ApoA-I initially removes SPM in the presence of ABCA1. Then the decreasing SPM in plasma membrane triggers PC-PLC activity. PC-PLC catalyzes the hydrolysis of PC to generate DAG. And, finally, DAG activates PKCα and then PKCα phosphorylates ABCA1. (C) The interaction of apoA-I with ABCA1 increases phosphorylation of JAK2 and thus activates JAK2. The activated JAK2 further activates STAT3. (D) The interaction of apoA-I with ABCA1 results in activation of Cdc42 and subsequent phosphorylations of PAK-1 and p54^JNK and polymerization of actin. (E) ApoA-I induces Ca²⁺ influx into cells. The rise in cytosolic Ca²⁺ then triggers Ca²⁺-dependent calcineurin pathway. The influx of Ca²⁺ also increases phosphorylation of JAK2.