scholarly journals Molecular cloning of a second form of rac protein kinase.

1991 ◽  
Vol 2 (12) ◽  
pp. 1001-1009 ◽  
Author(s):  
P F Jones ◽  
T Jakubowicz ◽  
B A Hemmings
Keyword(s):  
Amino Acids ◽  
Protein Kinase ◽  
Protein Kinases ◽  
Cell Lines ◽  
Catalytic Domain ◽  
Cell Types ◽  
In Vitro Translation ◽  
Cdna Libraries ◽  
Beta Form

A novel serine/threonine protein kinase (termed rac-PK) has recently been identified and cloned from cDNA libraries derived from the human cell lines MCF-7 and WI38. A second form of this protein kinase, termed rac protein kinase beta, has been identified from cDNAs derived from the same cell lines. These two closely related forms show 90% homology, although the beta form with a predicted Mr 60,200 has a carboxyl terminal extension of 40 amino acids in comparison to the alpha form. This extension has a high serine content with 11 serine residues in the last 30 amino acids. The beta form of the protein has been shown by both in vitro translation and bacterial expression to be approximately 5000 Da larger than the alpha form. rac protein kinase beta is encoded by a 3.4-kb transcript and the alpha form is encoded by a 3.2-kb mRNA. Using gene-specific probes both transcripts were detected in all cell types analyzed, although levels of expression were different for the two forms. The catalytic domain of rac protein kinase beta shows a high degree of homology to both the protein kinase C and cyclic AMP-dependent protein kinase families, and hence rac protein kinases appear to represent a new subfamily of the second messenger serine/threonine protein kinases.

Characterization of a dual plant protein kinase (FsPK1) up-regulated by abscisic acid and calcium and specifically expressed in dormant seeds ofFagus sylvaticaL.

2003 ◽  
Vol 13 (4) ◽  
pp. 261-271 ◽  
Author(s):  
O. Lorenzo ◽  
C. Nicolás ◽  
G. Nicolás ◽  
D. Rodríguez
Keyword(s):  
Abscisic Acid ◽  
Protein Kinase ◽  
Protein Kinases ◽  
Catalytic Domain ◽  
Consensus Sequence ◽  
Calcium Dependent ◽  
Localization Signal ◽  
Rapid Amplification

An abscisic acid (ABA)-induced cDNA fragment encoding a putative protein kinase (PK) was obtained by differential screening of a cDNA library fromFagus sylvaticaseeds. The full-length clone, named FsPK1, was produced by 5′ rapid amplification of cDNA ends (RACE) extension. This clone contained the 11 catalytic domains present in all protein kinases, but displayed unusual characteristics found only in a few plant PKs. FsPK1 exhibits features of both serine/threonine and tyrosine protein kinases within the catalytic domain, a putative nuclear localization signal within the regulatory domain and the consensus sequence involved in binding of 14-3-3 proteins. The catalytic domain, expressed inEscherichia colias a fusion protein, showed Ca2+-dependentin vitrokinase activity and dual serine/threonine and tyrosine specificity. Transcription of theFsPK1gene was reduced by seed stratification at 4°C, and clearly increased when seeds were treated with 0.1 mM ABA, correlating with the inhibition of germination. Interestingly,FsPK1transcripts were enhanced when ABA (0.1 mM) and calcium (1 mM) were added together, while the addition of EGTA (calcium chelator) and 3,4,5,-trimethoxibenzoic acid 8-(diethylamino) octyl ester (TMB-8, a calcium antagonist) decreased its expression. Furthermore,FsPK1transcript expression was tissue specific and accumulated only in ABA-treated seeds, but not in any ABA-treated vegetative tissues examined. These results suggest that the expression of the corresponding protein could be related to the inhibition of germination mediated by ABA in a calcium-dependent pathway.

NSP-encoded reticulons, neuroendocrine proteins of a novel gene family associated with membranes of the endoplasmic reticulum

1994 ◽  
Vol 107 (9) ◽  
pp. 2403-2416 ◽  
Author(s):  
H.J. van de Velde ◽  
A.J. Roebroek ◽  
N.H. Senden ◽  
F.C. Ramaekers ◽  
W.J. Van de Ven
Keyword(s):  
Amino Acids ◽  
Endoplasmic Reticulum ◽  
Gene Family ◽  
Biochemical Characterization ◽  
Smooth Endoplasmic Reticulum ◽  
Dendritic Tree ◽  
Cell Types ◽  
In Vitro Translation ◽  
Amino Terminal

The novel NSP gene was previously shown to encode, among a variety of neuroendocrine cell types, two 3′-overlapping transcripts, a 3.4 kb one for NSP-A (776 amino acids) and a 1.8 kb one for NSP-C (208 amino acids). The deduced proteins, which were predicted to possess distinct amino-terminal regions, appeared to exhibit some architectural resemblance to known neuroendocrine proteins. In this paper the biochemical characterization and subcellular localization of the two proteins is addressed. In vitro translation of NSP-A and -C RNA produced proteins of about 135 and 23 kDa, respectively. Proteins of similar molecular mass were also detected in immunoprecipitation and western blot analyses of neural and endocrine cells using specific anti-NSP-A or -C antisera; some heterogeneity of NSP-A was observed. NSP-A, but not NSP-C, appeared to be highly phosphorylated and preferentially on serine residues. In immunocytochemical studies, we demonstrated that NSP-A and -C are associated with the endoplasmic reticulum; NSP-A was found to co-localize with SERCA2b, a membrane-associated Ca(2+)-ATPase of the endoplasmic reticulum. In Purkinje cells, we found NSP-immunostaining in the perikaryon, the extensive dendritic tree and the axon, also suggesting association with the smooth endoplasmic reticulum. Biochemical studies of NSP-A provided evidence that NSP-A is strongly associated with microsomal membranes and analysis of deletion mutants of NSP-A revealed that the hydrophobic carboxy-terminal portion of the protein, which is also present in NSP-C, is critical for membrane binding. Through database searches, finally, we found two different NSP-related sequences, one in a sequenced region of human chromosome 19, and the second in a human, pancreatic islet-derived partial cDNA, suggesting that the NSP gene is the prototype of a larger gene family. The results of our studies seem to indicate that the NSP-encoded proteins are novel, membrane-anchored components of the endoplasmic reticulum for which we propose the name reticulons.

scholarly journals AH/PH domain-mediated interaction between Akt molecules and its potential role in Akt regulation.

1995 ◽  
Vol 15 (4) ◽  
pp. 2304-2310 ◽  
Author(s):  
K Datta ◽  
T F Franke ◽  
T O Chan ◽  
A Makris ◽  
S I Yang ◽  
...  
Keyword(s):  
Amino Acids ◽  
Protein Kinase ◽  
Catalytic Domain ◽  
Protein Complexes ◽  
Ph Domain ◽  
Terminal Portion ◽  
Protein Protein Interaction ◽  
Kinase C ◽  
Nih 3T3

The cytoplasmic serine-threonine protein kinase coded for by the c-akt proto-oncogene features a protein kinase C-like catalytic domain and a unique NH2-terminal domain (AH domain). The AH domain is a member of a domain superfamily whose prototype was observed in pleckstrin (pleckstrin homology, or PH, domain). In this communication, we present evidence that the AH/PH domain is a domain of protein-protein interaction which mediates the formation of Akt protein complexes. The interaction between c-akt AH/PH domains is highly specific, as determined by the failure of this domain to bind AKT2. The AH/PH domain-mediated interactions depend on the integrity of the entire domain. Akt molecules with deletions of the NH2-terminal portion (amino acids 11 to 60) and AH/PH constructs with deletions of the C-terminal portion of this domain (amino acids 107 to 147) fail to interact with c-akt. To determine the significance of these findings, we carried out in vitro kinase assays using Akt immunoprecipitates from serum-starved and serum-starved, platelet-derived growth factor-stimulated NIH 3T3 cells. Addition of maltose-binding protein-AH/PH fusion recombinant protein, which is expected to bind Akt, to the immunoprecipitates from serum-starved cells induced the activation of the Akt kinase.

scholarly journals Characterization of a Tomato Protein Kinase Gene Induced by Infection by Potato spindle tuber viroid

2000 ◽  
Vol 13 (9) ◽  
pp. 903-910 ◽  
Author(s):  
Rosemarie W. Hammond ◽  
Yan Zhao
Keyword(s):  
Protein Kinase ◽  
Protein Kinases ◽  
Catalytic Domain ◽  
Potato Spindle Tuber Viroid ◽  
Circular Rna ◽  
Sequence Motifs ◽  
Kinase Gene ◽  
Viroid Infection ◽  
Protein Kinase Gene

Viroids—covalently closed, circular RNA molecules in the size range of 250 to 450 nucleotides—are the smallest known infectious agents and cause a number of diseases of crop plants. Viroids do not encode proteins and replicate within the nucleus without a helper virus. In many cases, viroid infection results in symptoms of stunting, epinasty, and vein clearing. In our study of the molecular basis of the response of tomato cv. Rutgers to infection by Potato spindle tuber viroid (PSTVd), we have identified a specific protein kinase gene, pkv, that is transcriptionally activated in plants infected with either the intermediate or severe strain of PSTVd, at a lower level in plants inoculated with a mild strain, and not detectable in mock-inoculated plants. A full-length copy of the gene encoding the 55-kDa PKV (protein kinase viroid)-induced protein has been isolated and sequence analysis revealed significant homologies to cyclic nucleotide-dependent protein kinases. Although the sequence motifs in the catalytic domain suggest that it is a serine/threonine protein kinase, the recombinant PKV protein autophosphorylates in vitro on serine and tyrosine residues, suggesting that it is a putative member of the class of dual-specificity protein kinases.

scholarly journals Translational and Structural Requirements of the Early Nodulin Gene enod40, a Short-Open Reading Frame-Containing RNA, for Elicitation of a Cell-Specific Growth Response in the Alfalfa Root Cortex

2001 ◽  
Vol 21 (1) ◽  
pp. 354-366 ◽  
Author(s):  
Carolina Sousa ◽  
Christina Johansson ◽  
Celine Charon ◽  
Hamid Manyani ◽  
Christof Sautter ◽  
...  
Keyword(s):  
Amino Acids ◽  
Biological Activity ◽  
Rna Structure ◽  
Open Reading Frames ◽  
In Vitro Translation ◽  
Cortical Cells ◽  
Root Cortex ◽  
Reading Frame ◽  
Early Nodulin

ABSTRACT A diversity of mRNAs containing only short open reading frames (sORF-RNAs; encoding less than 30 amino acids) have been shown to be induced in growth and differentiation processes. The early nodulin geneenod40, coding for a 0.7-kb sORF-RNA, is expressed in the nodule primordium developing in the root cortex of leguminous plants after infection by symbiotic bacteria. Ballistic microtargeting of this gene into Medicago roots induced division of cortical cells. Translation of two sORFs (I and II, 13 and 27 amino acids, respectively) present in the conserved 5′ and 3′ regions ofenod40 was required for this biological activity. These sORFs may be translated in roots via a reinitiation mechanism. In vitro translation products starting from the ATG of sORF I were detectable by mutating enod40 to yield peptides larger than 38 amino acids. Deletion of a Medicago truncatula enod40 region between the sORFs, spanning a predicted RNA structure, did not affect their translation but resulted in significantly decreased biological activity. Our data reveal a complex regulation of enod40action, pointing to a role of sORF-encoded peptides and structured RNA signals in developmental processes involving sORF-RNAs.

Identification and characterization of a novel sucrose-non-fermenting protein kinase/AMP-activated protein kinase-related protein kinase, SNARK

2001 ◽  
Vol 355 (2) ◽  
pp. 297-305 ◽  
Author(s):  
Diana L. LEFEBVRE ◽  
Yahong BAI ◽  
Nazanin SHAHMOLKY ◽  
Monika SHARMA ◽  
Raymond POON ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Cellular Response ◽  
Catalytic Domain ◽  
Metabolic Stress ◽  
Glucose Deprivation ◽  
Protein Band ◽  
Northern Blotting ◽  
Significant Similarity ◽  
Amp Activated Protein Kinase

Subtraction hybridization after the exposure of keratinocytes to ultraviolet radiation identified a differentially expressed cDNA that encodes a protein of 630 amino acid residues possessing significant similarity to the catalytic domain of the sucrose-non-fermenting protein kinase (SNF1)/AMP-activated protein kinase (AMPK) family of serine/threonine protein kinases. Northern blotting and reverse-transcriptase-mediated PCR demonstrated that mRNA transcripts for the SNF1/AMPK-related kinase (SNARK) were widely expressed in rodent tissues. The SNARK gene was localized to human chromosome 1q32 by fluorescent in situ hybridization. SNARK was translated in vitro to yield a single protein band of approx. 76kDa; Western analysis of transfected baby hamster kidney (BHK) cells detected two SNARK-immunoreactive bands of approx. 76-80kDa. SNARK was capable of autophosphorylation in vitro; immunoprecipitated SNARK exhibited phosphotransferase activity with the synthetic peptide substrate HMRSAMSGLHLVKRR (SAMS) as a kinase substrate. SNARK activity was significantly increased by AMP and 5-amino-4-imidazolecarboxamide riboside (AICAriboside) in rat keratinocyte cells, implying that SNARK might be activated by an AMPK kinase-dependent pathway. Furthermore, glucose deprivation increased SNARK activity 3-fold in BHK fibroblasts. These findings identify SNARK as a glucose- and AICAriboside-regulated member of the AMPK-related gene family that represents a new candidate mediator of the cellular response to metabolic stress.

scholarly journals Respiratory-induced coenzyme Q biosynthesis is regulated by a phosphorylation cycle of Cat5p/Coq7p

2011 ◽  
Vol 440 (1) ◽  
pp. 107-114 ◽  
Author(s):  
Alejandro Martín-Montalvo ◽  
Isabel González-Mariscal ◽  
Sergio Padilla ◽  
Manuel Ballesteros ◽  
David L. Brautigan ◽  
...  
Keyword(s):  
Amino Acids ◽  
Protein Kinase ◽  
Regulatory Mechanism ◽  
Coenzyme Q ◽  
In Vitro Assays ◽  
Respiratory Metabolism ◽  
Total Absence ◽  
Kinase C ◽  
Pkc Protein Kinase C

CoQ6 (coenzyme Q6) biosynthesis in yeast is a well-regulated process that requires the final conversion of the late intermediate DMQ6 (demethoxy-CoQ6) into CoQ6 in order to support respiratory metabolism in yeast. The gene CAT5/COQ7 encodes the Cat5/Coq7 protein that catalyses the hydroxylation step of DMQ6 conversion into CoQ6. In the present study, we demonstrated that yeast Coq7 recombinant protein purified in bacteria can be phosphorylated in vitro using commercial PKA (protein kinase A) or PKC (protein kinase C) at the predicted amino acids Ser20, Ser28 and Thr32. The total absence of phosphorylation in a Coq7p version containing alanine instead of these phospho-amino acids, the high extent of phosphorylation produced and the saturated conditions maintained in the phosphorylation assay indicate that probably no other putative amino acids are phosphorylated in Coq7p. Results from in vitro assays have been corroborated using phosphorylation assays performed in purified mitochondria without external or commercial kinases. Coq7p remains phosphorylated in fermentative conditions and becomes dephosphorylated when respiratory metabolism is induced. The substitution of phosphorylated residues to alanine dramatically increases CoQ6 levels (256%). Conversely, substitution with negatively charged residues decreases CoQ6 content (57%). These modifications produced in Coq7p also alter the ratio between DMQ6 and CoQ6 itself, indicating that the Coq7p phosphorylation state is a regulatory mechanism for CoQ6 synthesis.

scholarly journals Expression of the Metalloproteinase ADAM8 Is Upregulated in Liver Inflammation Models and Enhances Cytokine Release In Vitro

2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Tanzeela Awan ◽  
Aaron Babendreyer ◽  
Justyna Wozniak ◽  
Abid Mahmood Alvi ◽  
Viktor Sterzer ◽  
...  
Keyword(s):  
Cell Lines ◽  
Inflammatory Mediators ◽  
Liver Tissue ◽  
Stellate Cell ◽  
Hepatoma Cell ◽  
Cell Types ◽  
Chronic Liver ◽  
Liver Inflammation ◽  
Tnf Α

Acute and chronic liver inflammation is driven by cytokine and chemokine release from various cell types in the liver. Here, we report that the induction of inflammatory mediators is associated with a yet undescribed upregulation of the metalloproteinase ADAM8 in different murine hepatitis models. We further show the importance of ADAM8 expression for the production of inflammatory mediators in cultured liver cells. As a model of acute inflammation, we investigated liver tissue from lipopolysaccharide- (LPS-) treated mice in which ADAM8 expression was markedly upregulated compared to control mice. In vitro, stimulation with LPS enhanced ADAM8 expression in murine and human endothelial and hepatoma cell lines as well as in primary murine hepatocytes. The enhanced ADAM8 expression was associated with an upregulation of TNF-α and IL-6 expression and release. Inhibition studies indicate that the cytokine response of hepatoma cells to LPS depends on the activity of ADAM8 and that signalling by TNF-α can contribute to these ADAM8-dependent effects. The role of ADAM8 was further confirmed with primary hepatocytes from ADAM8 knockout mice in which TNF-α and IL-6 induction and release were considerably attenuated. As a model of chronic liver injury, we studied liver tissue from mice undergoing high-fat diet-induced steatohepatitis and again observed upregulation of ADAM8 mRNA expression compared to healthy controls. In vitro, ADAM8 expression was upregulated in hepatoma, endothelial, and stellate cell lines by various mediators of steatohepatitis including fatty acid (linoleic-oleic acid), IL-1β, TNF-α, IFN-γ, and TGF-β. Upregulation of ADAM8 was associated with the induction and release of proinflammatory cytokines (TNF-α and IL-6) and chemokines (CX3CL1). Finally, knockdown of ADAM8 expression in all tested cell types attenuated the release of these mediators. Thus, ADAM8 is upregulated in acute and chronic liver inflammation and is able to promote inflammation by enhancing expression and release of inflammatory mediators.

scholarly journals Multiple mechanisms for the phosphorylation of C-terminal regulatory sites in rabbit muscle glycogen synthase expressed in COS cells

1996 ◽  
Vol 313 (1) ◽  
pp. 45-50 ◽  
Author(s):  
Alexander V. SKURAT ◽  
Peter J. ROACH
Keyword(s):  
Protein Kinase ◽  
Protein Kinases ◽  
Glycogen Synthase ◽  
Glycogen Synthase Kinase ◽  
Glycogen Synthase Kinase 3 ◽  
Rabbit Muscle ◽  
Cos Cells ◽  
Additional Mutation ◽  
Regulatory Sites

Glycogen synthase can be inactivated by sequential phosphorylation at the C-terminal residues Ser652 (site 4), Ser648 (site 3c), Ser644 (site 3b) and Ser640 (site 3a) catalysed by glycogen synthase kinase-3. In vitro, glycogen synthase kinase-3 action requires that glycogen synthase has first been phosphorylated at Ser656 (site 5) by casein kinase II. Recently we demonstrated that inactivation is linked only to phosphorylation at site 3a and site 3b, and that, in COS cells, modification of these sites can occur by alternative mechanisms independent of any C-terminal phosphorylations [Skurat and Roach (1995) J. Biol. Chem. 270, 12491-12497]. To address these mechanisms multiple Ser → Ala mutations were introduced in glycogen synthase such that only site 3a or site 3b remained intact. Additional mutation of Arg637 → Gln eliminated phosphorylation of site 3a, indicating that Arg637 may be important for recognition of site 3a by its corresponding protein kinase(s). Similarly, additional mutation of Pro645 → Ala eliminated phosphorylation of site 3b, indicating a possible involvement of ‘proline-directed’ protein kinase(s). Mutation of Arg637 alone did not activate glycogen synthase as expected from the loss of phosphorylation at site 3a. Rather, mutation of both Arg637 and the Ser → Ala substitution at site 3b was required for substantial activation. The results suggest that sites 3a and 3b can be phosphorylated independently of one another by distinct protein kinases. However, phosphorylation of site 3b can potentiate phosphorylation of site 3a, by an enzyme such as glycogen synthase kinase-3.

Mitogen stimulation of Na+-H+ exchange: differential involvement of protein kinase C

1987 ◽  
Vol 253 (2) ◽  
pp. C219-C229 ◽  
Author(s):  
L. L. Muldoon ◽  
G. A. Jamieson ◽  
A. C. Kao ◽  
H. C. Palfrey ◽  
M. L. Villereal
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Cell Types ◽  
Intact Cells ◽  
Kinase C ◽  
Protein Kinase C Activity ◽  
Human Fibroblast Strains ◽  
Stimulation Of

The mitogen-induced activation of Na+-H+ exchange was investigated in two cultured human fibroblast strains (HSWP and WI-38 cells) that, based on previous studies, differed in their response to the tumor-promoting phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA) (L. M. Vincentini and M. L. Villereal, Proc. Natl. Acad. Sci. USA 82: 8053-8056, 1985). The role of protein kinase C in the activation of Na+-H+ exchange was investigated by comparing the effects of TPA on Na+ influx, in vitro phosphorylation, and in vivo phosphorylation in both cell types. Although both cell types have significant quantities of protein kinase C activity that can be activated by TPA in intact cells, the addition of TPA to intact cells stimulates Na+ influx in WI-38 cells but not in HSWP cells, indicating that in HSWP cells the stimulation of protein kinase C is not sufficient to activate the Na+-H+ exchanger. Cells were then depleted of protein kinase C activity by chronic treatment with high doses of TPA. Both HSWP and WI-38 cells were rendered protein kinase C deficient by this treatment as determined by in vitro and in vivo phosphorylation studies. Protein kinase C-deficient HSWP cells lose the ability for TPA to inhibit the serum-induced activation of Na+-H+ exchange, but there is no reduction in the stimulation of Na+ influx by serum, bradykinin, vasopressin, melittin, or vanadate, indicating that protein kinase C activity is not necessary for the mitogen-induced activation of Na+-H+ exchange in HSWP cells by agents known to stimulate phosphatidylinositol turnover (G. A. Jamieson and M. Villereal. Arch. Biochem. Biophys. 252: 478-486, 1987). In contrast, depletion of protein kinase C activity in WI-38 cells significantly reduces both the TPA- and the serum-induced activation of the Na+-H+ exchange system, suggesting that protein kinase C activity is necessary for at least a portion of the mitogen-induced activation of the Na+-H+ exchanger in WI-38 cells. These results indicate that the mechanisms for regulating Na+-H+ exchange can differ dramatically between different types of fibroblasts.

Sign in / Sign up

Export Citation Format

Share Document