Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.11.24 (mitogen-activated protein kinase)
 95,810 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

MAPK(mitogen activated protein kinase) is a kind of Ser/Thr protein kinase. The MAPKs play an important role in several different signal transduction pathways. The MAPKs may also have a role in morphorgenesis of Candida albicans. An oligonucleotide probe was used to screen novel MAPKs in C. albicans. All MAPKs shared high homogeneity in their eleven kinase subdomains, especially subdoman VII and VIII. In subdomain VII, nearly all MAPKs have the same KIDFGLAR sequence, and the two known MAPKs in C. albicans CEK1 and MKC1 have only one different nucleotide in that DNA sequence. This probe was hybridized with C. albicans genomic DNA. Under stringent conditions, the probe could only hybridize with CEK1 and MKC1 gene fragment. But when hybridized at 40 degrees in non-SDS solution, two novel bands appeared. This condition was used to screen SC5314 DNA library, and many positive clones with different hybridization density were obtained. The strongest hybridization clones were identified to contain CEK1 and MKC1 gene. From the stronger positive hybridization clones, two novel genes were identified. The first gene, named CRK1(CDC2-related protein kinase 1), shared high homogeneity to MAPKs, but was not of them. It is closest to SGV1 from S. cerevisiae (with homology 47%) and PITALRE from human (with homology 41%), both of which are CDC2-related protein kinases. The second gene called CEK2(Candida albicans extracelluar signal-regulated kinase 2) is a novel MAPK of Candida albicans, which shares the highest identity with CEK1 and its S. cerevisiae homologs, FUS3 and KSS1, two redundant MAPKs in yeast pheromone response and morphogenesis.
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PMID:Molecular Cloning of MAPK Gene Family Using Synthetic Oligonucleotide Probe. 1211 67

MST1 is a member of the Sterile-20 family of cytoskeletal, stress, and apoptotic kinases. MST1 is activated by phosphorylation at previously unidentified sites. This study examines the role of phosphorylation at several sites and effects on kinase activation. We define Thr(183) in subdomain VIII as a primary site of phosphoactivation. Thr(187) is also critical for kinase activity. Phosphorylation of MST1 in subdomain VIII was catalyzed by active MST1 via intermolecular autophosphorylation, enhanced by homodimerization. Active MST1 (wild-type or T183E), but not inactive Thr(183)/Thr(187) mutants, was also highly autophosphorylated at the newly identified Thr(177) and Thr(387) residues. Cells expressing active MST1 were mostly detached, whereas with inactive MST1, adhesion was normal. Active MKK4, JNK, caspase-3, and caspase-9 were detected in the detached cells. These cells also contained all autophosphorylated and essentially all caspase-cleaved MST1. Similar phenotypes were elicited by a caspase-insensitive D326N mutant, suggesting that kinase activity, but not cleavage of MST1, is required. Interestingly, an S327E mutant mimicking Ser(327) autophosphorylation was also caspase-insensitive, but only when expressed in caspase-3-deficient cells. Together, these data suggest a model whereby MST1 activation is induced by existing, active MST kinase, which phosphorylates Thr(183) and possibly Thr(187). Dimerization promotes greater phosphorylation. This leads to induction of the JNK signaling pathway, caspase activation, and apoptosis. Further activation of MST1 by caspase cleavage is best promoted by caspase-3, although this appears to be unnecessary for signaling and morphological responses.
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PMID:Mapping of MST1 kinase sites of phosphorylation. Activation and autophosphorylation. 1222 93

MAPK/ERK kinase kinase 1 (MEKK1) is a mitogenactivated protein kinase kinase kinase (MAP3K) of the stress-induced JNK pathway. Once activated, MEKK1 phosphorylates the MAP2K MKK4, which in turn phosphorylates JNK. MEKK1 also has the capacity to activate IKK, the central protein kinase of the NF-kappa B pathway. The molecular determinants responsible for the ability of MEKK1 to recognize specific substrates are poorly understood. We report here that select point mutations in subdomain VIII of the protein kinase domain of MEKK1 (MEKK1 Delta) differentially affect its ability to activate MKK4 and IKK, and consequently AP1 and NF-kappa B reporter genes. Moreover, binding of MKK4 to MEKK1 Delta protects the latter from cleavage at an engineered protease target site in subdomain VIII. Collectively these results provide evidence that subdomain VIII of MEKK1 is involved not only in binding to, but also in discrimination of, protein substrates.
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PMID:Subdomain VIII is a specificity-determining region in MEKK1. 1450 Jul 27

Activated protein C (APC), a natural anticoagulant, is formed from protein C by the action of thrombin bound to thrombomodulin on the endothelial cell surface. APC regulates the coagulation system by inactivating the activated form of factors V and VIII in the presence of protein S. Tumor necrosis factor-alpha (TNF-alpha) plays critical roles in the development of disseminated intravascular coagulation, acute respiratory distress syndrome and shock in sepsis by inducing endothelial cell damage through activation of neutrophils. APC reduces the pulmonary endothelial cell injury and hypotension in rats administered endotoxin (ET) by inhibiting TNF-alpha production through inhibition of its transcription. Furthermore, APC reduces the ischemia/reperfusion-induced renal injury and the stress-induced gastric mucosal injury in rats. Inhibition by APC of the endothelial cell damage inhibited the decrease in the endothelial production of prostacyclin in vivo. These therapeutic effects could not be attributed to its anticoagulant effects, but to inhibition of TNF-alpha production. APC inhibits ET-induced TNF-alpha production in vitro in human monocytes by inhibiting activation of NFkappaB and AP-1 by inhibiting degradation of IkappaB and mitogen-activated protein kinase pathways, respectively. Recombinant APC was reported to reduce the mortality of patients with severe sepsis. These observations strongly suggest that APC might be involved not only in regulation of the coagulation system, but in regulation of inflammatory responses by preventing endothelial cell injury. Furthermore, APC reduced the spinal cord injury induced by compression-trauma or ischemia/reperfusion by inhibiting TNF-alpha production in rats, suggesting that APC may be a potential therapeutic agent for spinal cord injury in which only limited therapeutic measures are currently available.
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PMID:Prevention of endothelial cell injury by activated protein C: the molecular mechanism(s) and therapeutic implications. 1532 May 13

Optic nerve transection results in retinal ganglion cell (RGC) death in adult mammals, after the alteration of gene expression of RGCs. To elucidate the molecular mechanism by which axotomy induces RGC death, we isolated the molecules up-regulated after optic nerve transection. One of these, axotomy-related [corrected] gene (ARG)357, an 898-amino-acid [corrected] protein containing a complete serine-threonine kinase domain, was isolated from a subtraction library of the rat retina. The sequence showed that this gene was a rat homolog of human c-Jun N-terminal kinase (JNK) inhibitory kinase and so belonged to the germinal center kinase-VIII subfamily of Sterile20s protein kinase. We designated ARG357 as rat JNK inhibitory kinase (JIK). Rat JIK was expressed ubiquitously in various tissues and was highly expressed in the retina, with selective expression in RGCs. After axotomy, BimEL and Hrk, which are BH3-only proteins, and rat JIK were up-regulated in RGCs. Overexpression of rat JIK in neuronal cells up-regulated the expression of BimEL, but not that of Hrk. These results indicate that JIK may contribute to axotomy-induced RGC death by up-regulating the expression of BH3-only protein.
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PMID:JNK inhibitory kinase is up-regulated in retinal ganglion cells after axotomy and enhances BimEL expression level in neuronal cells. 1609 29

Mitogen-activated protein kinase kinase 7 (MKK7) is a direct activator of the mitogen-activated protein kinase family member c-Jun N-terminal kinase (JNK). MKK7 activates JNK via phosphorylation of a threonine and tyrosine residue in a Thr-Pro-Tyr motif within kinase subdomain VIII. To date at least six different isoforms of murine MKK7 have been identified. However, only three isoforms of human MKK7 have been reported. We report here the cloning of hMKK7gamma1, the human homolog of murine MKK7gamma1. Expression of hMKK7gamma1 mRNA was assessed and transcripts were present in low levels in placenta, fetal liver, and skeletal muscle. PCR results indicate that hMKK7gamma1 is expressed in various normal tissues, tumors, and in synoviocytes from rheumatoid and osteoarthritis patients. Recombinant hMKK7gamma1 can be phosphorylated and activated by MEKK1. Further studies will provide insight into the role for hMKK7gamma1 versus other MKK7 isoforms.
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PMID:Cloning and expression of human mitogen-activated protein kinase kinase 7gamma1. 1644 2

This study investigates the role of p38 MAPK, inducible nitric oxide synthase (iNOS), and the intrinsic pathway signaling in male germ cell death in rats after hormonal deprivation by a potent GnRH antagonist treatment. Germ cell apoptosis, involving exclusively middle (VII-VIII) stages, was activated by d 5 after GnRH antagonist treatment. Initiation of germ cell apoptosis was preceded by p38 MAPK activation and induction of iNOS. p38 MAPK activation and iNOS induction were further accompanied by a marked perturbation of the BAX/BCL-2 rheostat, cytochrome c, and DIABLO release from mitochondria, caspase activation, and poly(ADP-ribose) polymerase cleavage. Concomitant administration of aminoguanidine, a selective iNOS inhibitor, significantly prevented hormone deprivation-induced germ cell apoptosis. Inhibitors of iNOS or p38 MAPK were also effective in preventing human male germ cell apoptosis induced by hormone-free culture conditions. Together, these results establish a new signal transduction pathway involving p38 MAPK and iNOS that, through activation of the intrinsic pathway signaling, promotes male germ cell death in response to a lack of hormonal stimulation across species.
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PMID:Involvement of p38 mitogen-activated protein kinase and inducible nitric oxide synthase in apoptotic signaling of murine and human male germ cells after hormone deprivation. 1646 70

The biochemical basis that regulates the timely and selective opening of the blood-testis barrier (BTB) to migrating preleptotene/leptotene spermatocytes at stage VIII of the epithelial cycle in adult rat testes is virtually unknown. Recent studies have shown that cytokines (e.g. transforming growth factor (TGF)-beta3) may play a crucial role in this event. However, much of this information relies on the use of toxicants (e.g. CdCl(2)), making it difficult to relay these findings to normal testicular physiology. Here we report that overexpression of TGF-beta3 in primary Sertoli cells cultured in vitro indeed perturbed the tight junction (TJ) barrier with a concomitant decline in the production of BTB constituent proteins as follows: occludin, N-cadherin, and ZO-1. Additionally, local administration of TGF-beta3 to testes in vivo was shown to reversibly perturb the BTB integrity and Sertoli-germ cell adhesion via the p38 MAPK and ERK signaling pathways. Most importantly, the simultaneous activation of p38 and ERK signaling pathways is dependent on the association of the TGF-beta3-TbetaR1 complex with adaptors TAB1 and CD2AP because if TbetaR1 was associated preferentially with CD2AP, only Sertoli-germ cell adhesion was perturbed without compromising the BTB. Collectively, these data illustrate that local production of TGF-beta3, and perhaps other TGF-betas and cytokines, by Sertoli and germ cells into the microenvironment at the BTB during spermatogenesis transiently perturbs the BTB and Sertoli-germ cell adhesion to facilitate germ cell migration when the activated TbetaRI interacts with adaptors TAB1 and CD2AP. However, TGF-beta3 selectively disrupts Sertoli-germ cell adhesion in the seminiferous epithelium to facilitate germ cell migration without compromising BTB when TbetaRI interacts only with adaptor CD2AP.
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PMID:Differential interactions between transforming growth factor-beta3/TbetaR1, TAB1, and CD2AP disrupt blood-testis barrier and Sertoli-germ cell adhesion. 1661 54

SED1, also known as MFG-E8, is a secreted protein composed of two EGF repeats (the second of which contains an RGD motif) and two discoidin/Factor V/VIII C domains. SED1 is expressed by a wide range of cell types, where it participates in diverse cellular interactions, such as sperm binding to the egg coat and macrophage recognition of apoptotic lymphocytes. Although SED1 was originally identified as a milk protein, its function in the mammary gland remains unclear; suggested functions include inhibition of viral infection and clearance of apoptotic cells during mammary gland involution. We report here that SED1 has an unexpected obligatory role during mammary gland development. Unlike that seen in WT glands, SED1-null glands show severely reduced branching from epithelial ducts and from terminal end buds, which are thin and poorly developed. SED1 is expressed by both luminal and myoepithelial cells in the developing epithelial duct, and binds to alpha(v) integrin receptors on myoepithelial cells leading to MAPK activation and cell proliferation. The absence of SED1 leads to greatly reduced levels of activated MAPK and a concomitant reduction in cell proliferation and branching throughout the epithelial tree. These results suggest that SED1 contributes, at least partly, to the intercellular signaling between luminal and myoepithelial cells that is required for branching morphogenesis.
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PMID:The EGF repeat and discoidin domain protein, SED1/MFG-E8, is required for mammary gland branching morphogenesis. 1729 48

Leukemic cell apoptosis may be enhanced by appropriate oxidative stress. We report here the mechanism of Jurkat cell apoptosis by monochloramine (NH(2)Cl), a neutrophil-derived oxidant. NH(2)Cl induced caspase-dependent apoptosis, which was preceded by cytochrome c and Smac/Diablo release from mitochondria. Within 10min of NH(2)Cl treatment, c-Jun N-terminal kinase (JNK) activation and elevation of cytosolic Ca(2+) were observed. JNK inhibitors (SP600125 or JNK inhibitor VIII) significantly suppressed the apoptosis as well as caspase cleavage and cytochrome c release. In contrast, Ca(2+) chelation by EGTA+acetoxymethyl-EGTA had no effects on apoptosis. Our results indicated that JNK activation contributed most importantly to the NH(2)Cl-induced apoptosis.
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PMID:Activation of c-Jun N-terminal kinase is essential for oxidative stress-induced Jurkat cell apoptosis by monochloramine. 1871 60


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