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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)
Many eukaryotic genes are regulated by cAMP through a conserved cAMP response element (CRE). Here we show that, in the pancreatic islet cell line Tu6, a well-characterized CRE in the somatostatin gene does not provide cAMP responsiveness but functions as an essential element for its basal activity. DNA-binding and functional analyses indicate that the cAMP-responsive factor CREB regulates somatostatin expression in these cells without requirement for phosphorylation at the
protein kinase A
-regulated Ser-133 phosphorylation site. In addition to the CRE site, cell-specific expression of the somatostatin gene requires a second promoter element, which binds the recently characterized
LIM
family protein Isl-1. Thus, Isl-1 and CREB appear to synergize on the somatostatin promoter to stimulate high-level expression in Tu6 cells. The ability of CREB to function in a phosphorylation-independent manner suggests a mechanism by which this protein can regulate gene transcription.
...
PMID:The LIM family transcription factor Isl-1 requires cAMP response element binding protein to promote somatostatin expression in pancreatic islet cells. 135 85
We have selected yeast mutants that exhibit a constitutively active pheromone-response pathway in the absence of the beta subunit of the trimeric G protein. Genetic analysis of one such mutant revealed that it contained recessive mutations in two distinct genes, both of which contributed to the constitutive phenotype. One mutation identifies the RGA1 locus (Rho GTPase activating protein), which encodes a protein with homology to GAP domains and to
LIM
domains. Deletion of RGA1 is sufficient to activate the pathway in strains lacking the G beta subunit. Moreover, in wild-type strains, deletion of RGA1 increases signaling in the pheromone pathway, whereas over-expression of RGA1 dampens signaling, demonstrating that Rga1p functions as a negative regulator of the pheromone response pathway. The second mutation present in the original mutant proved to be an allele of a known gene, PBS2, which encodes a putative protein kinase that functions in the high osmolarity stress pathway. The pbs2 mutation enhanced the rga1 mutant phenotype, but by itself did not activate the pheromone pathway. Genetic and two-hybrid analyses indicate that an important target of Rga1p is Cdc42p, a p21 GTPase required for polarity establishment and bud emergence. This finding coupled with recent experiments with mammalian and yeast cells indicating that Cdc42p can interact with and activate Ste20p, a
protein kinase
that operates in the pheromone pathway, leads us to suggest that Rga1p controls the activity of Cdc42p, which in turn controls the magnitude of signaling in the pheromone pathway via Ste20p.
...
PMID:Mutation of RGA1, which encodes a putative GTPase-activating protein for the polarity-establishment protein Cdc42p, activates the pheromone-response pathway in the yeast Saccharomyces cerevisiae. 749 91
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.
...
PMID:LIMK-1 and LIMK-2, two members of a LIM motif-containing protein kinase family. 765 34
The RBTN1 and RBTN2 genes are activated by distinct translocations involving chromosome 11 in some T cell acute leukaemias. The RBTN proteins belong to the
LIM
family which comprises proteins with one, two or three cysteine-rich
LIM
domains, sometimes together with homeodomains or
protein kinase
domains. The RBTN1 and RBTN2 proteins comprise only tandem
LIM
domains. We report that RBTN1 and RBTN2 proteins are capable of supporting transcriptional transactivation of specific reporter genes in transfection assays. The results, using intact proteins or fusions with the homeodomain of the heterologous protein Isl-1, show that this transcriptional activation ability resides in the NH2-terminal parts of both proteins. The use of yeast assays with RBTN2 shows that RBTN2 forms homodimers and that the NH2-terminal 27 amino acids are sufficient to facilitate transcriptional transactivation. These data expand the functional diversity of the LIM-domain protein family and they augment the previously defined relationship between chromosomal translocations and transcriptional activation.
...
PMID:Functional diversity of LIM proteins: amino-terminal activation domains in the oncogenic proteins RBTN1 and RBTN2. 773 80
Using the cDNA fragment of chicken c-sea receptor tyrosine kinase as a probe, we isolated from a chicken lung cDNA library overlapping cDNA clones encoding a novel
protein kinase
, which we termed LIM-kinase (LIMK). The predicted polypeptide of 642 amino acid residues contains remarkable structural features, composed of the N-terminal two tandemly arrayed
LIM
/double zinc finger motifs and the C-terminal unusual
protein kinase
domain. To our knowledge, a
protein kinase
containing the
LIM
motif in the molecule has not heretofore been described. The
protein kinase
domain of LIMK shares highly conserved residues with the known protein kinases, but LIMK is unique in that it contains the sequence DLNSHN in subdomain VIB and a short, highly basic insert sequence, which may function as a signal for nuclear localization, between subdomain VII and VIII in the
protein kinase
domain. Northern blot analysis revealed that the single species of LIMK mRNA of 3.8 kb is expressed predominantly in the lung, and faintly in the kidney, liver, brain, spleen, gizzard, and intestine. As the
LIM
motif is thought to be involved in protein-protein interactions by binding to another
LIM
motif, and is often present in the homeodomain-containing proteins involved in cell fate determination and in the oncogenic nuclear proteins (rhombotins), it is likely that LIMK is involved in developmental or oncogenic processes through interactions with these
LIM
-containing proteins.
...
PMID:Molecular cloning of a chicken lung cDNA encoding a novel protein kinase with N-terminal two LIM/double zinc finger motifs. 785 84
By low-stringency screening of a human hepatoma HepG2 cell cDNA library, using the genomic fragment of chick c-sea receptor tyrosine kinase as a probe, we isolated overlapping cDNAs encoding a novel
protein kinase
, which we termed LIM-kinase (LIMK).* The predicted open reading frame encodes a 647-amino-acid polypeptide containing a putative protein kinase structure in the C-terminal half. In addition, LIMK has two repeats of cysteine-rich
LIM
/double zinc finger motif at the most N-terminus. To our knowledge, this is the first
protein kinase
seen to contain the
LIM
motif(s) in the molecule. Although the
protein kinase
domain of LIMK has highly conserved sequence elements of protein kinases, phylogenetic analysis revealed that LIMK cannot be classified into any subfamily of known protein kinases. Northern blot analysis revealed that the single species of LIMK mRNA of 3.3 kb was expressed in various human epithelial and hematopoietic cell lines. In rat tissues, LIMK mRNA was expressed in the brain, at the highest level.
LIM
is suggested to be involved in protein-protein interactions by binding to another
LIM
motif. As the LIM domain is frequently present in the homeodomain-containing transcriptional regulators and oncogenic nuclear proteins, LIMK may be involved in developmental or oncogenic processes through interactions with these
LIM
-containing proteins.
...
PMID:Identification of a human cDNA encoding a novel protein kinase with two repeats of the LIM/double zinc finger motif. 818 54
We previously isolated human cDNA coding for LIMK1 (LIM motif-containing protein kinase-1), a putative protein kinase containing two
LIM
motifs at the N terminus and an unusual
protein kinase
domain at the C terminus. In the present study, we isolated human cDNA encoding LIMK2, a second member of a LIMK family, with a domain structure similar to LIMK1 and 50% overall amino acid identity with LIMK1. The
protein kinase
domains of LIMK1 and LIMK2 are unique in that they contain an unusual sequence motif Asp-Leu-Asn-Ser-His-Asn in subdomain VIB and a highly basic insert between subdomains VII and VIII. Expression patterns of LIMK1 and LIMK2 mRNAs in human tissues differ significantly. Chromosomal localization of human LIMK1 and LIMK2 genes was assigned to 7q11.23 and 22q12, respectively, by fluorescence in situ hybridization. The Myc epitope-tagged LIMK1 and LIMK2 proteins transiently expressed in COS cells exhibited serine/threonine-specific kinase activity toward myelin basic protein and histone in in vitro kinase assay. Immunofluorescence and subcellular fractionation analysis revealed that Myc-tagged LIMK1 and LIMK2 were localized mainly in the cytoplasm. The "native" LIMK1 protein endogenously expressed in A431 epidermoid carcinoma cells also exhibited serine/threonine kinase activity. The specific activity of native LIMK1 from A431 cells was apparently much higher than that of "recombinant" LIMK1 ectopically expressed in COS cells, hence, it is likely that there is a mechanism, by which native LIMK1 is activated. A 140-kDa tyrosine-phosphorylated protein (pp140) was co-immunoprecipitated with native LIMK1 form A431 cell lysates; therefore, pp140 may be a LIMK1-associated protein involved in the regulation of LIMK1 function.
...
PMID:Identification and characterization of a novel family of serine/threonine kinases containing two N-terminal LIM motifs. 853 3
Throughout vertebrate embryogenesis, membrane bound and intracellular protein kinases govern the fundamental decisions necessary for coordinated cell growth and differentiation. Here we have characterized limk, a novel
protein kinase
with serine threonine substrate specificity which also contains two
LIM
domains. We used Northern blot and in situ hybridization techniques to determine its pattern of expression in early mouse development. Between 7.5 and 8.5 d.p.c., limk is expressed in three broad domains within the embryo, the neuroectodermal of the prospective forebrain and mid-brain regions, the cardiac mesoderm, and the newly formed definitive endodermal derivatives the foregut and hindgut. By 10.0 d.p.c. limk remains prominently expressed in the ventromedial regions of the developing forebrain and midbrain, with continued expression in the hindgut. In adults limk is expressed most prominently in the brain. Additionally we have shown that limk is most abundantly expressed in the trophoblast giant cells, from 4.5 d.p.c. onwards. Moreover, high levels of limk expression is associated with the overt formation of giant cells from diploid progenitors, suggesting an involvement for limk in the differentiation of this highly specialized extra-embryonic cell type.
...
PMID:The murine LIM-kinase gene (limk) encodes a novel serine threonine kinase expressed predominantly in trophoblast giant cells and the developing nervous system. 854 Dec 8
The ret/ptc2 papillary thyroid cancer oncogene, an oncogenic form of the c-Ret receptor tyrosine kinase, is the product of a somatic crossover event fusing the dimerization domain of the type Ialpha regulatory subunit of
cyclic AMP-dependent protein kinase
(RI) with the tyrosine kinase domain of c-Ret. Mitogenic activity of Ret/ptc2 required dimerization via the N terminus of RI and a tyrosine residue located C-terminal to the kinase core of Ret, Tyr-586 (Durick, K., Yao, V. J., Borrello, M. G., Bongarzone, I., Pierotti, M. A. and Taylor, S. S. (1995) J. Biol. Chem. 270, 24642-24645). Using the yeast two-hybrid system, Ret/ptc2 binding proteins were identified, and the sites of interaction with Ret/ptc2 were mapped. The SH2 domains of phospholipase Cgamma and Grb10 were both identified, and binding depended on phosphorylation of Tyr-539 and Tyr-429, respectively. These interactions, however, were not required for mitogenic signaling. The second of the three
LIM
domains in Enigma (Wu, R. Y., and Gill, G. N. (1994) J. Biol. Chem. 269, 25085-25090) was also identified as a Ret/ptc2 binding domain. Enigma, a 455-residue protein, was discovered based on its interaction with the insulin receptor through the C-terminal LIM domain. Although the association with Enigma required Tyr-586 of Ret/ptc2, the interaction was phosphorylation-independent. In contrast to the SH2 interactions, disruption of the interaction with Enigma abolished Ret/ptc2 mitogenic signaling, suggesting that LIM domain recognition of an unphosphorylated tyrosine-based motif is required for Ret signal transduction.
...
PMID:Mitogenic signaling by Ret/ptc2 requires association with enigma via a LIM domain. 866 82
To identify genes important for human cognitive development, we studied Williams syndrome (WS), a developmental disorder that includes poor visuospatial constructive cognition. Here we describe two families with a partial WS phenotype; affected members have the specific WS cognitive profile and vascular disease, but lack other WS features. Submicroscopic chromosome 7q11.23 deletions cosegregate with this phenotype in both families. DNA sequence analyses of the region affected by the smallest deletion (83.6 kb) revealed two genes, elastin (ELN) and LIM-kinase1 (LIMK1). The latter encodes a novel
protein kinase
with
LIM
domains and is strongly expressed in the brain. Because ELN mutations cause vascular disease but not cognitive abnormalities, these data implicate LIMK1 hemizygosity in imparied visuospatial constructive cognition.
...
PMID:LIM-kinase1 hemizygosity implicated in impaired visuospatial constructive cognition. 868 88
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