Mutations in protein kinase subdomain X differentially affect MEKK2 and MEKK1 activity.
MAPK/ERK kinase kinase 2 (MEKK2) is a member of the mitogen-activated protein kinase kinase kinase (MAP3K) family of protein kinases. MAP3Ks are components of a three-tiered protein kinase pathway in which a MAP3K phosphorylates and activates a mitogen-activated protein kinase kinase (MAP2K), which in turn activates a mitogen-activated protein kinase (MAPK). We have previously identified residues within protein kinase subdomain X in the MAP3K, MEKK1, that are critical for its interaction with the MAP2K, MKK4, and MEKK1-induced MKK4 activation. We report here that kinase subdomain X also plays a critical role in MEKK2 activity. Select point mutations in subdomain X impair MEKK2 phosphorylation of the MAP2Ks, MKK7 and MEK5, abolish MEKK2-induced activation of the MAPKs, JNK1 and ERK5, and diminish MEKK2-dependent activation of an AP-1 reporter gene. Interestingly, the spectrum of mutations in subdomain X of MEKK2 that affects its activity is overlapping with but not identical to those that have effects on MEKK1. Thus, mutations in subdomain X differentially affect MEKK2 and MEKK1.
Huang
Jianhe
J
Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, 605 Stellar Chance Labs, 422 Curie Blvd., Philadelphia, PA 19104, USA.
Tu
Zheng
Z
Lee
Frank S
FS
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D019556:COS Cells; D002522:Chlorocebus aethiops; D017931:DNA Primers; D004789:Enzyme Activation; D006367:HeLa Cells; D006801:Humans; D048728:MAP Kinase Kinase Kinase 1; D048730:MAP Kinase Kinase Kinase 2; D048748:MAP Kinase Kinase Kinase 3; D048768:MAP Kinase Kinase Kinase 4; D020930:MAP Kinase Kinase Kinases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D011494:Protein Kinases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D015183:Restriction Mapping; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors / Q000378:metabolism; D014162:Transfection
D017931:DNA Primers; D011994:Recombinant Proteins; D014157:Transcription Factors; D011494:Protein Kinases; D017346:Protein Serine-Threonine Kinases; D048728:MAP Kinase Kinase Kinase 1; D048730:MAP Kinase Kinase Kinase 2; D048748:MAP Kinase Kinase Kinase 3; D048768:MAP Kinase Kinase Kinase 4; D020930:MAP Kinase Kinase Kinases; C482576:MAP3K1 protein, human; C482618:MAP3K2 protein, human; C482625:MAP3K3 protein, human; C482779:MAP3K4 protein, human; C482578:Map3k1 protein, mouse; C482619:Map3k2 protein, mouse; C482626:Map3k3 protein, mouse; C482780:Map3k4 protein, mouse