December 3, 2012

Macrophages are our little Pac-Man cells that gobble up the nasty pathogens that we may come into contact with. They’re importance is undeniable, and the images of macrophages doing their thing are always fascinating to me. Today’s image is from a paper describing the role of the protein Bcl10 in the process. 

Phagocytosis is the process during which a cell engulfs cellular debris or pathogens. Macrophages employ phagocytosis to rid the body of infectious agents, cellular debris in the lung, and necrotic tissue throughout the body. Phagocytosis requires regulation of actin polymerization and dynamics for the extension and then closure of a phagocytic cup that engulfs the target material. A recent paper describes the role of the NF-κB signaling protein Bcl10 in actin and membrane remodeling in human macrophages. Marion and colleagues found that without Bcl10, phagocytosis begins but then stops with accumulated actin. Bcl10 regulates actin polymerization in cups, which allows the vesicle exocytosis that causes membrane extension of the phagocytic cup. In the images above, macrophages were incubated with red blood cells (red) to track phagocytosis 5 minutes (left column) and 10 minutes (right column) after the start of the assay. Control macrophages (top) are able to phagocytose red blood cells after a few minutes into the assay (arrows point to membrane deformations indicative of phagocytosed particles). Cells lacking Bcl10 (bottom), however, are not able to complete engulfment of the red blood cells, and have shorter and disorganized membrane extensions compared with control cells. 

Marion, S., Mazzolini, J., Herit, F., Bourdoncle, P., Kambou-Pene, N., Hailfinger, S., Sachse, M., Ruland, J., Benmerah, A., Echard, A., Thome, M., & Niedergang, F. (2012). The NF-κB Signaling Protein Bcl10 Regulates Actin Dynamics by Controlling AP1 and OCRL-Bearing Vesicles Developmental Cell, 23 (5), 954-967 DOI: 10.1016/j.devcel.2012.09.021
Copyright ©2012 Elsevier Ltd. All rights reserved.