Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.11.1 (protein kinase)
 81,284 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Expression of mRNAs in the rat testis encoding cyclic AMP (cAMP)-dependent protein kinases (PKAs) was studied. A microdissection method was used to isolate 10 pools of seminiferous tubules representing various stages of the cycle of the seminiferous epithelium in combination with Northern blots and in situ hybridization. The results showed a differential expression of the four isoforms of the regulatory subunits (PKA-R) at various stages of the cycle. RI alpha mRNA was detected at approximately the same levels at all stages while expression of RI beta mRNA was low at stages XIII-III, started to increase at stages IV-V, and reached a maximum at stages VIII-XI. The level of RII alpha mRNA was low at stages II-VI, increased markedly at stage VIIa,b, and reached maximal levels at stages VIIc,d and VIII, followed by a reduced expression at later stages, RII beta mRNA levels increased significantly at stage VI with maximal levels at stages VII and VIII. In situ hybridization of sections from the adult rat testis revealed RI alpha mRNA in the layers of pachytene spermatocytes and round spermatids of all stages. RI beta mRNA was detected over late pachytene spermatocytes and round spermatids of stages VII-XIII. RII alpha mRNA was seen in the layers of round spermatids of stages VII-VIII and elongating spermatids of later stages while RII beta mRNA was detected only in the round spermatid region of stages VII-VIII and in some tubules of stages I-VI. These data show that mRNAs encoding PKA-R are expressed in a stage-specific manner in differentiating male germ cells with different patterns of expression for each subunit; this suggests specific roles for these protein kinases at different times of spermatogenesis.
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PMID:Stage- and cell-specific expression of cyclic adenosine 3',5'-monophosphate-dependent protein kinases in rat seminiferous epithelium. 132

Increases in the plant hormone abscisic acid (ABA) initiate water-stress responses in plants. We present evidence that a transcript with homology to protein kinases is induced by ABA and dehydration in wheat. A 1.2-kilobase cDNA clone (PKABA1) was isolated from an ABA-treated wheat embryo cDNA library by screening the library with a probe developed by polymerase chain reaction amplification of serine/threonine protein kinase subdomains VIb to VIII. The deduced amino acid sequence of the PKABA1 clone contains the features of serine/threonine protein kinases, including homology with all 12 conserved regions of the catalytic domain. PKABA1 transcript levels are barely detectable in growing seedlings but are induced dramatically when plants are subjected to dehydration stress. The PKABA1 transcript can also be induced by supplying low concentrations of ABA, and coordinate increases in ABA levels and PKABA1 mRNA occur when seedlings are water-stressed. Identification of this ABA-inducible transcript with homology to protein kinases provides a basis for examining the role of protein phosphorylation in plant responses to dehydration.
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PMID:Isolation of a wheat cDNA clone for an abscisic acid-inducible transcript with homology to protein kinases. 143 7

The SNF1 protein kinase is required for expression of glucose-repressed genes in response to glucose deprivation. The SNF4 protein is physically associated with SNF1 and positively affects the kinase activity. We report here the characterization of a dominant mutation, SNF1-G53R, that was isolated as a suppressor of the requirement for SNF4. The mutant SNF1-G53R protein is still responsive to SNF4 but has greatly elevated kinase activity in immune complex assays; in contrast, the activity is wild type in a protein blot assay. Deletion of the region N-terminal to the kinase domain (codons 5-52) reduces kinase activity in vitro, but the mutant SNF1-delta N kinase is still dependent on SNF4. The N terminus is not required for the regulatory response to glucose. In gel filtration chromatography, the SNF1, SNF1-G53R and SNF1-delta N protein showed different elution profiles, consistent with differential formation of high molecular weight complexes. Taken together, the results suggest that the N terminus positively affects the function of the SNF1 kinase and may be involved in interaction with a positive effector other than SNF4. We also showed that the conserved threonine residue 210 in subdomain VIII, which is a phosphorylation site in other kinases, is essential for SNF1 activity. Finally, we present evidence that when the C terminus is deleted, overexpression of the SNF1 kinase domain is deleterious to the cell.
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PMID:N-terminal mutations modulate yeast SNF1 protein kinase function. 146 23

Limited proteolysis of catalytic and regulatory subunits of cyclic AMP-dependent protein kinase (A-pk), cyclic AMP phosphodiesterase, glycogen synthase, and histones by fungal protease (type XIX) was analyzed by the digested peptide bands in SDS polyacrylamide gel electrophoresis. The modulatory effects on proteolysis by nucleotides, polypeptides, and phospholipids may greatly depend on the intrinsic nature of substrates. The proteolysis of the regulatory subunit of A-pk and glycogen synthase was not regulated by nucleotides and nucleic acids. In comparison, phosphatidyl serine, cardiolipin, and pepstatin A stimulated the proteolysis of the catalytic subunit of A-pk. Whereas, lambda DNA (Hind III digest), t-RNA, GTP-, phosphatidyl serine, sphingosine inhibited the proteolysis of cyclic AMP phosphodiesterase. Moreover, MS2 RNA, lambda DNA, t-RNA, dGTP, Phosphatidyl serine, phosphatidyl inositol, antipain, and chymostatin exerted inhibitory proteolytic effect on histone VIII-S. Some of these agents also had similar inhibitory effect on other types of histones (types III-S and VII-S). The inhibitory effect of phosphatidyl serine on proteolysis of histone may be due to their interaction which was monitored by the drastic increase of uv absorbance.
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PMID:Regulation of fungal proteolysis on cyclic AMP-dependent protein kinase, cyclic AMP phosphodiesterase, glycogen synthase and histones. 165 82

We have cloned the cDNA of the heme-regulated eIF-2 alpha kinase (HRI) of rabbit reticulocytes. In vitro translation of mRNA transcribed from the HRI cDNA yields a 90-kDa polypeptide that exhibits eIF-2 alpha kinase activity and is recognized by a monoclonal antibody directed against authentic HRI. The open reading frame sequence of the HRI cDNA contains all 11 catalytic domains of protein kinases with consensus sequences of protein-serine/threonine kinases in conserved catalytic domains VI and VIII. The HRI cDNA also contains an insert of approximately 140 amino acids between catalytic domains V and VI. The HRI cDNA coding sequence has extensive homology to GCN2 protein kinase of Saccharomyces cerevisiae and to human double-stranded-RNA-dependent eIF-2 alpha kinase. This observation suggests that GCN2 protein kinase may be an eIF-2 alpha kinase in yeast. In addition, HRI has an unusually high degree of homology to three protein kinases (NimA, Wee1, and CDC2) that are involved in the regulation of the cell cycle.
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PMID:Cloning of the cDNA of the heme-regulated eukaryotic initiation factor 2 alpha (eIF-2 alpha) kinase of rabbit reticulocytes: homology to yeast GCN2 protein kinase and human double-stranded-RNA-dependent eIF-2 alpha kinase. 167 35

The activity of the catalytic subunit of cyclic AMP-dependent protein kinase (A-PK), utilizing type II-S, III-S histone or protamine (free base) as a substrate, was augmented in the presence of regulatory protein including calmodulin, S-100 protein, parvalbumin, or troponin. However, inhibition by calmodulin or S-100 but stimulation by parvalbumin or troponin on this A-PK subunit was observed when II-S histone was replaced by V-S, VI-S, VII-S, or VIII-S histone. In addition, the stimulatory effect of calmodulin or S-100 on this A-PK subunit utilizing III-S histone was greatly diminished when half the dose of III-S was replaced by other histones in a bi-mixed form.
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PMID:Modulation of the catalytic subunit of cyclic AMP-dependent protein kinase by calmodulin, S-100 protein, parvalbumin and troponin. 374 31

Protein kinase activity (EC 2.7.1.37) of buffalo spermatozoa is distributed in the head (22%) and midpieces + tails (74%). Extraction of sperm heads with 0.1% Triton X-100 solubilized 35--40 of the protein kinase activity and the remaining 60--65% was associated tightly with the sperm chromatin. That the sperm chromatin preparation was pure was established by recording its spectrum at 320/260 nm (0.07), determining its composition (protein:DNA ratio, 0.79), electron microscope examination and through the assay of marker enzymes. Extraction of the chromatin preparation with 1 M-NaCl only partly solubilized the protein kinase activity while treatment with DNase in the presence of dithiothreitol inactivated the nuclear protein kinase. The chromatin-associated protein kinase activity had a broad pH optimum (7.6--8.4), an essential requirement for Mg2+ and ATP as a phosphate donor. Histones and non-histone proteins served as substrates, the preferred substrate being arginine rich histone VIII followed by casein and phosvitin. Nuclear protein kinase activity was neither stimulated by cyclic AMP nor inhibited by purified muscle protein kinase inhibitor. It is suggested that chromatin-associated protein kinase (Type III protein kinase) may be involved in the control of DNA-template activity.
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PMID:Association of buffalo sperm protein kinase with sperm chromatin. 712 Jan 98

Focal adhesion kinase (FAK) is a widely expressed nonreceptor protein-tyrosine kinase implicated in integrin-mediated signal transduction pathways and in the process of oncogenic transformation by v-Src. Elevation of FAK's phosphotyrosine content, following both cell adhesion to extracellular matrix substrata and cell transformation by Rous sarcoma virus, correlates directly with an increased kinase activity. To help elucidate the role of FAK phosphorylation in signal transduction events, we used a tryptic phosphopeptide mapping approach to identify tyrosine sites of phosphorylation responsive to both cell adhesion and Src transformation. We have identified four tyrosines, 397, 407, 576, and 577, which are phosphorylated in mouse BALB/3T3 fibroblasts in an adhesion-dependent manner. Tyrosine 397 has been previously recognized as the major site of FAK autophosphorylation. Phosphorylation of tyrosines 407, 576, and 577, which are previously unrecognized sites, is significantly elevated in the presence of c-Src in vitro and v-Src in vivo. Tyrosines 576 and 577 lie within catalytic subdomain VIII--a region recognized as a target for phosphorylation-mediated regulation of protein kinase activity. We found that maximal kinase activity of FAK immune complexes requires phosphorylation of both tyrosines 576 and 577. Our results indicate that phosphorylation of FAK by Src (or other Src family kinases) is an important step in the formation of an active signaling complex.
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PMID:Tyrosine phosphorylation of focal adhesion kinase at sites in the catalytic domain regulates kinase activity: a role for Src family kinases. 752 76

The Ste20p protein kinase was immunopurified from yeast cells and analyzed in an in vitro assay system. Ste20p immune complexes exhibited autophosphorylating activity at serine and threonine residues and specifically phosphorylated a bacterially expressed glutathione S-transferase (GST) fusion of Ste11p (a mitogen-activated protein or extracellular signal-regulated kinase kinase (MEK) kinase homologue) at serine and threonine residues. In contrast, GST fusions either of Ste7p (a MEK homologue) or the beta-subunit of the mating response G-protein and immunoprecipitated Ste5p were not phosphorylated by the Ste20p immune complexes. Myelin basic protein was identified as an excellent in vitro substrate, whereas histone H1 was only poorly phosphorylated. Evidence was obtained that autophosphorylation might play a regulatory role for the in vitro kinase activity. The in vitro activity was found to be Ca(2+)-independent. Both the in vivo and in vitro activities were abolished by mutational changes of either the conserved lysine residue 649 within the ATP binding site or threonine 777 between the catalytic subdomains VII and VIII. Wild-type Ste20p and the catalytically inactive T777A mutant were identified as phosphoproteins in vivo. The phosphorylation occurred at serine and threonine residues independent of pheromone stimulation. Based on the genetically determined significance of Ste20p in pheromone signal transduction and on our in vitro studies, we propose the model that Ste20p represents a yeast MEK kinase kinase whose function is to link G-protein-coupled receptors through G beta gamma to a mitogen-activated protein kinase module.
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PMID:Molecular characterization of Ste20p, a potential mitogen-activated protein or extracellular signal-regulated kinase kinase (MEK) kinase kinase from Saccharomyces cerevisiae. 760 57

We previously isolated human cDNA encoding LIM-kinase (LIMK), a putative protein kinase which contains two repeats of the LIM motif at the N-terminus and a protein kinase consensus sequence at the C-terminus. Using as a probe a cDNA fragment of human LIMK, we isolated from a rat brain cDNA library cDNA clones encoding two distinct protein kinases (termed LIMK-1 and LIMK-2) related to human LIMK. LIMK-1 shares with human LIMK 95% of the total 647 amino acids and is probably a rat equivalent of human LIMK. LIMK-2 has an overall sequence and a domain structure similar to that of human LIMK and rat LIMK-1, but overall identity is 50-51% at the amino acid level. Like human LIMK, the protein kinase domains of rat LIMK-1 and -2 contain a characteristic sequence DLNSHN in subdomain VIB and a highly basic insert between subdomain VII and VIII. LIMK-1 and -2 are therefore closely related but distinct members of a novel LIM-containing protein kinase subfamily. Several forms of LIMK-2 transcripts encoding proteins that are N-terminally modified and/or C-terminally truncated are generated by alternative splicing or alternative initiation. Northern blot analysis revealed the expression of LIMK-1 mRNA predominantly in the brain and the expression of LIMK-2 mRNA in various tissues in the rat. Antibody raised against LIMK-1 specifically immunoprecipitated and identified in Rat2 fibroblast cells a 72 kDa protein, which has no detectable autophosphorylating activity but is capable of phosphorylating serine and threonine residues of myelin basic protein, by in vitro kinase reaction. As the LIMK family kinases have unique structural features, they are likely to have specific functions in previously uncharacterized signaling pathways.
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PMID:LIMK-1 and LIMK-2, two members of a LIM motif-containing protein kinase family. 765 34


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