Regulation of tyrosine phosphorylation in macrophage phagocytosis and chemotaxis

Macrophages display a large variety of surface receptors that are critical for their normal cellular functions in host defense, including finding sites of infection (chemotaxis) and removing foreign particles (phagocytosis). However, inappropriate regulation of these processes can lead to human diseases. Many of these receptors utilize tyrosine phosphorylation cascades to initiate and terminate signals leading to cell migration and clearance of infection. Actin remodeling dominates these processes and many regulators have been identified. This review focuses on how tyrosine kinases and phosphatases regulate actin dynamics leading to macrophage chemotaxis and phagocytosis.

► Phagocytosis and chemotaxis are very different processes.
► Both processes require robust, coordinated rearrangement of the actin cytoskeleton.
► Tyrosine kinases and phosphatases fine tune these processes.
► Many similarities exist in the signaling molecules used in these processes.
► However, specificity also exists between different receptors.