The polymorphonuclear leukocyte (PMN)-derived serine proteases play a key role in immune complex (IC)-mediated inflammation. However, the mechanisms by which these proteases regulate inflammatory response remain largely undefined. Here, we show that IC-activated cathepsin G- and neutrophil elastase-deficient (CG/NE) PMNs adhered normally to IC-coated surfaces but did not undergo CD11b clustering and failed to initiate cytoskeletal reorganization and cell spreading. As a result, CG/NE-deficient PMNs exhibited severe defects in MIP-2 secretion and reactive oxygen intermediates production. Exogenously added CG, but not proteolytically inactive CG, was sufficient to restore these defects. These findings identify an important role for CG in integrin-dependent PMN effector functions that are separate from and downstream of integrin-dependent adhesion. Copyright ©2005 by Elsevier Inc.
Raptis, S. Z., Shapiro, S. D., Simmons, P. M., Cheng, A. M., & Pham, C. T. N. (2005). Serine protease cathepsin G regulates adhesion-dependent neutrophil effector functions by modulating integrin clustering. Immunity, 22(6), 679–691. https://doi.org/10.1016/j.immuni.2005.03.015