Downstream components of RhoA required for signal pathway of superoxide formation during phagocytosis of serum opsonized zymosans in macrophages.
Rac1 and Rac2 are essential for the control of oxidative burst catalyzed by NADPH oxidase. It was also documented that Rho is associated with the superoxide burst reaction during phagocytosis of serum- (SOZ) and IgG-opsonized zymosan particles (IOZ). In this study, we attempted to reveal the signal pathway components in the superoxide formation regulated by Rho GTPase. Tat-C3 blocked superoxide production, suggesting that RhoA is essentially involved in superoxide formation during phagocytosis of SOZ. Conversely SOZ activated both RhoA and Rac1/2. Inhibition of RhoA-activated kinase (ROCK), an important downstream effector of RhoA, by Y27632 and myosin light chain kinase (MLCK) by ML-7 abrogated superoxide production by SOZ. Extracellular signaling-regulated kinase (ERK)1/2 and p38 mitogen-activated protein kinase (MAPK) were activated during phagocytosis of SOZ, and Tat-C3 and SB203580 reduced ERK1/2 and p38 MAPK activation, suggesting that RhoA and p38 MAPK may be upstream regulators of ERK1/2. Inhibition of ERK1/2, p38 MAPK, phosphatidyl inositol 3-kinase did not block translocation of RhoA to membranes, suggesting that RhoA is upstream to these kinases. Inhibition of RhoA by Tat-C3 blocked phosphorylation of p47(PHOX). Taken together, RhoA, ROCK, p38MAPK, ERK1/2, and p47(PHOX) may be subsequently activated, leading to activation of NADPH oxidase to produce superoxide.
Kim
Jun Sub
JS
Department of Biochemistry, College of Medicine, Hallym University, Chuncheon 220-702, Korea.
Kim
Jae Gyu
JG
Jeon
Chan Young
CY
Won
Ha Young
HY
Moon
Mi Young
MY
Seo
Ji Yeon
JY
Kim
Jong Il
JI
Kim
Jaebong
J
Lee
Jae Yong
JY
Choi
Soo Young
SY
Park
Jinseu
J
Yoon Park
Jung Han
JH
Ha
Kwon Soo
KS
Kim
Pyeung Hyeun
PH
Park
Jae Bong
JB
D000818:Animals; D002460:Cell Line; D002462:Cell Membrane; D003600:Cytosol; D004791:Enzyme Inhibitors / Q000494:pharmacology; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins; D016177:Macrophage-1 Antigen / Q000494:pharmacology; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D051379:Mice; D009219:Myosin-Light-Chain Kinase / Q000378:metabolism; D009895:Opsonin Proteins / Q000097:blood / Q000378:metabolism*; D010587:Phagocytosis; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D021381:Protein Transport; D015398:Signal Transduction; D013481:Superoxides / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D015054:Zymosan / Q000097:blood*; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism; D054460:rho-Associated Kinases; D020742:rhoA GTP-Binding Protein / Q000037:antagonists & inhibitors / Q000378:metabolism*
D004791:Enzyme Inhibitors; D047908:Intracellular Signaling Peptides and Proteins; D016177:Macrophage-1 Antigen; D009895:Opsonin Proteins; D013481:Superoxides; D015054:Zymosan; D017346:Protein Serine-Threonine Kinases; D054460:rho-Associated Kinases; D009219:Myosin-Light-Chain Kinase; D048049:Extracellular Signal-Regulated MAP Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D020742:rhoA GTP-Binding Protein; D013755:Tetradecanoylphorbol Acetate