Activation of the c-Jun N-Terminal Kinase Pathway by a Novel Protein Kinase Related to Human Germinal Center Kinase

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 94; no. 18; pp. 9687 - 9692
• Main Authors: Diener, Katrina, Wang, Xuhong Sunny, Chen, Cecil, Meyer, Christian F., Keesler, George, Zukowski, Mark, Tan, Tse-Hua, Yao, Zhengbin
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences of the United States of America 02-09-1997; National Acad Sciences; National Academy of Sciences; The National Academy of Sciences of the USA
• Subjects: Amino Acid Sequence; Amino acids; Antibodies; B lymphocytes; Biological Sciences; Calcium-Calmodulin-Dependent Protein Kinases - metabolism; Cells; Cellular biology; Cellular immunity; Cloning, Molecular; Complementary DNA; COS cells; Deoxyribonucleic acid; DNA; Enzyme Activation; HeLa cells; Humans; JNK Mitogen-Activated Protein Kinases; MAP Kinase Kinase 4; Mitogen-Activated Protein Kinase Kinases; Mitogen-Activated Protein Kinases; Molecular Sequence Data; Plasmids; Protein Kinases - genetics; Protein Kinases - isolation & purification; Protein Kinases - metabolism; Proteins; Sequence Alignment; Signal Transduction
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.94.18.9687

The c-Jun N-terminal kinase (JNK), or stress-activated protein kinase plays a crucial role in cellular responses stimulated by environmental stress and proinflammatory cytokines. However, the mechanisms that lead to the activation of the JNK pathway have not been elucidated. We have isolated a cDNA encoding a novel protein kinase that has significant sequence similarities to human germinal center kinase (GCK) and human hematopoietic progenitor kinase 1. The novel GCK-like kinase (GLK) has a nucleotide sequence that encodes an ORF of 885 amino acids with 11 kinase subdomains. Endogenous GLK could be activated by UV radiation and proinflammatory cytokine tumor necrosis factor α . When transiently expressed in 293 cells, GLK specifically activated the JNK, but not the p42/44MAPK/ extracellular signal-regulated kinase or p38 kinase signaling pathways. Interestingly, deletion of amino acids 353-835 in the putative C-terminal regulatory region, or mutation of Lys-35 in the putative ATP-binding domain, markedly reduced the ability of GLK to activate JNK. This result indicates that both kinase activity and the C-terminal region of GLK are required for maximal activation of JNK. Furthermore, GLK-induced JNK activation could be inhibited by a dominant-negative mutant of mitogen-activated protein kinase kinase kinase 1 (MEKK1) or mitogen-activated protein kinase kinase 4/SAPK/ERK kinase 1 (SEK1), suggesting that GLK may function upstream of MEKK1 in the JNK signaling pathway.