Characterization of the role of CaMKI-like kinase (CKLiK) in human granulocyte function.
Activation of granulocyte effector functions, such as induction of the respiratory burst and migration, are regulated by a variety of relatively ill-defined signaling pathways. Recently, we identified a novel Ca2+/calmodulin-dependent kinase I-like kinase, CKLiK, which exhibits restricted mRNA expression to human granulocytes. Using a novel antibody generated against the C-terminus of CKLiK, CKLiK was detected in CD34+-derived neutrophils and eosinophils, as well as in mature peripheral blood granulocytes. Activation of human granulocytes by N-formyl-methionyl-leucyl-phenylalanine (fMLP) and platelet-activating factor (PAF), but not the phorbol ester PMA (phorbol 12-myristate-13-acetate), resulted in induction of CKLiK activity, in parallel with a rise of intracellular Ca2+ [Ca2+]i. To study the functionality of CKLiK in human granulocytes, a cell-permeable CKLiK peptide inhibitor (CKLiK297-321) was generated which was able to inhibit kinase activity in a dose-dependent manner. The effect of this peptide was studied on specific granulocyte effector functions such as phagocytosis, respiratory burst, migration, and adhesion. Phagocytosis of Aspergillus fumigatus particles was reduced in the presence of CKLiK297-321 and fMLP-induced reactive oxygen species (ROS) production was potently inhibited by CKLiK297-321 in a dose-dependent manner. Furthermore, fMLP-induced neutrophil migration on albumin-coated surfaces was perturbed, as well as beta2-integrin-mediated adhesion. These findings suggest a critical role for CKLiK in modulating chemoattractant-induced functional responses in human granulocytes.
Verploegen
Sandra
S
Molecular Immunology Lab, Department of Immunology, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands.
Ulfman
Laurien
L
van Deutekom
Hanneke W M
HW
van Aalst
Corneli
C
Honing
Henk
H
Lammers
Jan-Willem J
JW
Koenderman
Leo
L
Coffer
Paul J
PJ
D018952:Antigens, CD34; D002118:Calcium / Q000378:metabolism; D054729:Calcium-Calmodulin-Dependent Protein Kinase Type 1; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000032:analysis / Q000037:antagonists & inhibitors / Q000502:physiology*; D002448:Cell Adhesion; D002465:Cell Movement; D002478:Cells, Cultured; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004804:Eosinophils / Q000737:chemistry; D006098:Granulocytes / Q000737:chemistry / Q000502:physiology*; D006801:Humans; D009504:Neutrophils / Q000737:chemistry; D010587:Phagocytosis; D012333:RNA, Messenger / Q000096:biosynthesis; D016897:Respiratory Burst; D015398:Signal Transduction
D018952:Antigens, CD34; D004791:Enzyme Inhibitors; D012333:RNA, Messenger; C517596:CAMK1 protein, human; C517601:CAMK1D protein, human; D054729:Calcium-Calmodulin-Dependent Protein Kinase Type 1; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D002118:Calcium