Figure 1.

Regulation of Ca²⁺ homeostasis by Pak1. Protein kinase PKA and phosphatase PP2A are associated with key Ca²⁺ handling and regulatory proteins, which in turn are linked to upstream signaling cascades. A balance of protein kinase and phosphatase activities is required to maintain normal cardiac functions. Pak1 also regulates hypertrophic signaling and gene expression of SERCA2a through other signaling pathways by activating its downstream effectors (e.g., JNK). (Liu et al., 2011; Wang et al., 2014a) (NCX: Na⁺-Ca²⁺ exchanger, PMCA: Plasma membrane Ca²⁺ ATPase, JNK: c-Jun N-terminal Kinase).