Ca²⁺ Signaling in Cytoskeletal Reorganization, Cell Migration, and Cancer Metastasis

Figure 2

Cytosolic Ca²⁺ levels are low in the front and high in the back of the migrating cell. The Ca²⁺ gradient is created by the differential distribution of plasma membrane Ca²⁺-ATPase (PMCA, shown as P in the illustration), resulting in higher pump activity to move cytosolic Ca²⁺ out of the cell in the front than the back. Low Ca²⁺ in the front “starves” myosin light chain kinase (MLCK), which is essential for its reactivity to local Ca²⁺ pulses. High Ca²⁺ in the back facilitates the turnover of stable focal adhesion complexes. (See Figure 4 and the text for more details.)