scholarly journals Identification of Yin-Yang Regulators and a Phosphorylation Consensus for Male Germ Cell-Associated Kinase (MAK)-Related Kinase

2006 ◽  
Vol 26 (22) ◽  
pp. 8639-8654 ◽  
Author(s):  
Zheng Fu ◽  
Katherine A. Larson ◽  
Raghu K. Chitta ◽  
Sirlester A. Parker ◽  
Benjamin E. Turk ◽  
...  
Keyword(s):  
Germ Cell ◽  
Phosphorylation Site ◽  
Site Directed Mutagenesis ◽  
Male Germ Cell ◽  
Intestinal Cell ◽  
Protein Phosphatase 5 ◽  
Extracellular Signal ◽  
Putative Phosphorylation Site ◽  
Yin Yang

ABSTRACT MAK (male germ cell-associated protein kinase) and MRK/ICK (MAK-related kinase/intestinal cell kinase) are human homologs of Ime2p in Saccharomyces cerevisiae and of Mde3 and Pit1 in Schizosaccharomyces pombe and are similar to human cyclin-dependent kinase 2 (CDK2) and extracellular signal-regulated kinase 2 (ERK2). MAK and MRK require dual phosphorylation in a TDY motif catalyzed by an unidentified human threonine kinase and tyrosine autophosphorylation. Herein, we establish that human CDK-related kinase CCRK (cell cycle-related kinase) is an activating T157 kinase for MRK, whereas active CDK7/cyclin H/MAT1 complexes phosphorylate CDK2 but not MRK. Protein phosphatase 5 (PP5) interacts with MRK in a complex and dephosphorylates MRK at T157 in vitro and in situ. Thus, CCRK and PP5 are yin-yang regulators of T157 phosphorylation. To determine a substrate consensus, we screened a combinatorial peptide library with active MRK. MRK preferentially phosphorylates R-P-X-S/T-P sites, with the preference for arginine at position −3 (P−3) being more stringent than for prolines at P−2 and P+1. Using the consensus, we identified a putative phosphorylation site (RPLT1080S) for MRK in human Scythe, an antiapoptotic protein that interacts with MRK. MRK phosphorylates Scythe at T1080 in vitro as determined by site-directed mutagenesis and mass spectrometry, supporting the consensus and suggesting Scythe as a physiological substrate for MRK.

scholarly journals Biochemical and Genetic Evidence for Participation of DevR in a Phosphorelay Signal Transduction Pathway Essential for Heterocyst Maturation in Nostoc punctiforme ATCC 29133

1999 ◽  
Vol 181 (14) ◽  
pp. 4430-4434 ◽  
Author(s):  
Kari D. Hagen ◽  
John C. Meeks
Keyword(s):  
Signal Transduction ◽  
Response Regulator ◽  
Phosphorylation Site ◽  
Signal Transduction Pathway ◽  
Site Directed Mutagenesis ◽  
Single Amino Acid ◽  
Insertion Mutant ◽  
Nostoc Punctiforme ◽  
Putative Phosphorylation Site

ABSTRACT In a test of the hypothesis that DevR is a response regulator protein that functions in a phosphorelay signal transduction system involved in heterocyst development in Nostoc punctiformeATCC 29133, purified affinity-tagged DevR was shown to be phosphorylated in vitro by the noncognate sensor kinase EnvZ. Site-directed mutagenesis was used to generate N. punctiforme mutants with single amino acid substitutions at the putative phosphorylation site of DevR. These mutants exhibited a Fox− phenotype like the original devRinsertion mutant UCD 311, consistent with a phosphotransferase role for DevR.

scholarly journals Intestinal Cell Kinase (ICK) Promotes Activation of mTOR Complex 1 (mTORC1) through Phosphorylation of Raptor Thr-908

2012 ◽  
Vol 287 (15) ◽  
pp. 12510-12519 ◽  
Author(s):  
Di Wu ◽  
Jessica R. Chapman ◽  
Lifu Wang ◽  
Thurl E. Harris ◽  
Jeffrey Shabanowitz ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Consensus Sequence ◽  
Phosphorylation Site ◽  
Intestinal Cell ◽  
Putative Phosphorylation Site ◽  
Mtorc1 Signaling ◽  
Mtor Complex 1 ◽  
Intestinal Cell Kinase

Intestinal cell kinase (ICK), named after its cloning origin, the intestine, is actually a ubiquitously expressed and highly conserved serine/threonine protein kinase. Recently we reported that ICK supports cell proliferation and G1 cell cycle progression. ICK deficiency significantly disrupted the mammalian target of rapamycin (mTOR) complex 1 (mTORC1) signaling events. However, the biological substrates that mediate the downstream signaling effects of ICK in proliferation and the molecular mechanisms by which ICK interacts with mTORC1 are not well defined. Our prior studies also provided biochemical evidence that ICK interacts with the mTOR/Raptor complex in cells and phosphorylates Raptor in vitro. In this report, we investigated whether and how ICK targets Raptor to regulate the activity of mTORC1. Using the ICK substrate consensus sequence [R-P-X-S/T-P/A/T/S], we identified a putative phosphorylation site, RPGT908T, for ICK in human Raptor. By mass spectrometry and a phospho-specific antibody, we showed that Raptor Thr-908 is a novel in vivo phosphorylation site. ICK is able to phosphorylate Raptor Thr-908 both in vitro and in vivo and when Raptor exists in protein complexes with or without mTOR. Although expression of the Raptor T908A mutant did not affect the mTORC1 integrity, it markedly impaired the mTORC1 activation by insulin or by overexpression of the small GTP-binding protein RheB under nutrient starvation. Our findings demonstrate an important role for ICK in modulating the activity of mTORC1 through phosphorylation of Raptor Thr-908 and thus implicate a potential signaling mechanism by which ICK regulates cell proliferation and division.

Nemo-like kinase promotes etoposide-induced apoptosis of male germ cell-derived GC-1 cells in vitro

FEBS Letters ◽  
2012 ◽  
Vol 586 (10) ◽  
pp. 1497-1503 ◽  
Author(s):  
Xiaowen Cheng ◽  
Junbo Liang ◽  
Yu Teng ◽  
Jun Fu ◽  
Shiying Miao ◽  
...  
Keyword(s):  
Germ Cell ◽  
Male Germ Cell ◽  
Induced Apoptosis

scholarly journals Characterization and Expression Analysis of Genes Encoding Phosphoenolpyruvate Carboxylase and Phosphoenolpyruvate Carboxylase Kinase of Lotus japonicus, a Model Legume

2003 ◽  
Vol 16 (4) ◽  
pp. 281-288 ◽  
Author(s):  
Tomomi Nakagawa ◽  
Tomoko Izumi ◽  
Mari Banba ◽  
Yosuke Umehara ◽  
Hiroshi Kouchi ◽  
...  
Keyword(s):  
Phosphoenolpyruvate Carboxylase ◽  
Root Nodules ◽  
Expression Patterns ◽  
Phosphorylation Site ◽  
Lotus Japonicus ◽  
Specific Protein ◽  
Mrna Levels ◽  
Model Legume ◽  
Putative Phosphorylation Site

Phosphoenolpyruvate carboxylases (PEPCs), one form of which in each legume species plays a central role in the carbon metabolism in symbiotic root nodules, are activated through phosphorylation of a conserved residue by a specific protein kinase (PEPC-PK). We characterized the cDNAs for two PEPC isoforms of Lotus japonicus, an amide-translocating legume that forms determinate nodules. One gene encodes a nodule-enhanced form, which is more closely related to the PEPCs in amide-type indeterminate nodules than those in ureide-type determinate nodules. The other gene is expressed in shoots and roots at a low level. Both forms have the putative phosphorylation site, Ser11. We also isolated a cDNA and the corresponding genomic DNA for PEPC-PK of L. japonicus. The recombinant PEPC-PK protein expressed in Escherichia coli phosphorylated recombinant maize C4-form PEPC efficiently in vitro. The level of mRNA for PEPC-PK was high in root nodules, and those in shoots and roots were also significant. In situ hybridization revealed that the expression patterns of the transcripts for PEPC and PEPC-PK were similar in mature root nodules, but were different in emerging nodules. When L. japonicus seedlings were subjected to prolonged darkness and subsequent illumination, the activity of PEPC-PK and the mRNA levels of both PEPC and PEPC-PK in nodules decreased and then recovered, suggesting that they are regulated according to the amounts of photosynthates transported from shoots.

scholarly journals The Transcription Factor GATA4 Is Activated by Extracellular Signal-Regulated Kinase 1- and 2-Mediated Phosphorylation of Serine 105 in Cardiomyocytes

2001 ◽  
Vol 21 (21) ◽  
pp. 7460-7469 ◽  
Author(s):  
Qiangrong Liang ◽  
Russell J. Wiese ◽  
Orlando F. Bueno ◽  
Yan-Shan Dai ◽  
Bruce E. Markham ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Dna Binding ◽  
Phosphorylation Site ◽  
Dominant Negative ◽  
Site Directed Mutagenesis ◽  
Mitogen Activated Protein Kinase ◽  
Cardiomyocyte Hypertrophy ◽  
Hypertrophic Growth ◽  
Extracellular Signal Regulated Kinase ◽  
Extracellular Signal

ABSTRACT The zinc finger-containing transcription factor GATA4 has been implicated as a critical regulator of multiple cardiac-expressed genes as well as a regulator of inducible gene expression in response to hypertrophic stimulation. Here we demonstrate that GATA4 is itself regulated by the mitogen-activated protein kinase signaling cascade through direct phosphorylation. Site-directed mutagenesis and phospho-specific GATA4 antiserum revealed serine 105 as the primary site involved in agonist-induced phosphorylation of GATA4. Infection of cultured cardiomyocytes with an activated MEK1-expressing adenovirus induced robust phosphorylation of serine 105 in GATA4, while a dominant-negative MEK1-expressing adenovirus blocked agonist-induced phosphorylation of serine 105, implicating extracellular signal-regulated kinase (ERK) as a GATA4 kinase. Indeed, bacterially purified ERK2 protein directly phosphorylated purified GATA4 at serine 105 in vitro. Phosphorylation of serine 105 enhanced the transcriptional potency of GATA4, which was sensitive to U0126 (MEK1 inhibitor) but not SB202190 (p38 inhibitor). Phosphorylation of serine 105 also modestly enhanced the DNA binding activity of bacterially purified GATA4. Finally, induction of cardiomyocyte hypertrophy with an activated MEK1-expressing adenovirus was blocked with a dominant-negative GATA4-engrailed-expressing adenovirus. These results suggest a molecular pathway whereby MEK1-ERK1/2 signaling regulates cardiomyocyte hypertrophic growth through the transcription factor GATA4 by direct phosphorylation of serine 105, which enhances DNA binding and transcriptional activation.

182 In Vitro Derivation of Male Germ Cells from Bovine Bone Marrow-Derived Mesenchymal Stem Cells

2018 ◽  
Vol 30 (1) ◽  
pp. 231
Author(s):  
J. Cortez ◽  
J. Bahamonde ◽  
J. Palomino ◽  
M. De los Reyes ◽  
C. Torres ◽  
...  
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Mesenchymal Stem Cells ◽  
Germ Cell ◽  
Mrna Expression ◽  
Male Germ Cell ◽  
Bovine Bone ◽  
Mrna Levels ◽  
Germ Cell Differentiation

During the last few years, the in vitro derivation of germ cell lineages from stem cells has emerged as an exciting new strategy for obtaining mature gametes. In vitro gamete derivation technology has potential applications as an alternative method for dissemination of elite animal genetics, production of transgenic animals, and conservation of endangered species. Germ cell differentiation and gametogenesis is a complex process and potential of different stem cell donors (i.e. SSC, ESC, iPSC) for in vitro male germ cell derivation has been inconsistent. Mesenchymal stem cells (MSC) may be suitable candidates for in vitro gamete derivation considering their (1) plasticity that is not limited to mesodermal derivatives, (2) availability of abundant tissues sources for isolation, (3) high proliferative potential, (4) simple and inexpensive isolation, and (5) high potential for cell therapy, including autologous or allogenic transplantation. The present study aimed to induce differentiation of MSC isolated from bone marrow derived from bovine male fetuses (bfMSC) into the germ cell lineage using an in vitro approach based on the exogenous effect of retinoic acid (RA) and bone morphogenetic protein 4 (BMP4). Differentiation media consisted in control media (DMEM with high glucose plus 10% fetal bovine serum, 100 IU mL−1 penicillin, 100 μg mL−1 streptomycin, and 0.25 μg mL−1amphotericin B) supplemented with RA (0.01, 0.1, or 1 µM) or BMP4 (10, 50, or 100 ng mL−1). Cell samples were obtained from differentiating and control bfMSC cultures and analysed for expression of housekeeping genes β-ACTIN and GAPDH, pluripotent genes OCT4 and NANOG, germ cell genes FRAGILLIS, STELLA, and VASA, male germ cell genes DAZL, PIWIl2, and STRA8, and meiotic biomarker SCP3 by quantitative-PCR (Q-PCR). OCT4, NANOG, and DAZL were immunodetected in undifferentiated and differentiated bfMSC using flow-cytometry analysis. The mRNA expression of DAZL was activated by RA or BMP4 supplementation, although no differences (P > 0.05) were detected among different concentrations. DAZL and NANOG mRNA levels increased (P < 0.05) from Day 7 to Day 21 during supplementation of RA (0.1 μM). In comparison, DAZL mRNA levels increased (P < 0.05) at Day 14 during supplementation of BMP4 (100 ng). OCT4 and SCP3 mRNA levels were not affected by RA or BMP4 treatments. Transcripts of FRAGILLIS, STELLA, VASA, PIWIl2, and STRA8 were not detected in control or differentiated bfMSC. Higher (P < 0.05) percentages of undifferentiated bfMSC were positive for NANOG (80.6%) and OCT4 (83.4%). DAZL- and NANOG-positive cells were 2.1% and 2.9%, and 95.9% and 97.8% at Days 0 and 21 of RA treatment, respectively. Data indicated that expression of germ cell biomarker DAZL in bfMSC is activated and increased after in vitro supplementation of RA and BMP4. Moreover, NANOG mRNA levels were regulated by RA treatment. Similar levels of SCP3 mRNA expression suggest that differentiated bfMSC were not induced into meiosis. Thus, exposure of bfMSC to RA or BMP4 under in vitro conditions might induce an early stage of premeiotic germinal differentiation.

Porcine nuclear transfer using somatic donor cells altered to express male germ cell function

2009 ◽  
Vol 21 (7) ◽  
pp. 882 ◽  
Author(s):  
Sangho Roh ◽  
Hye-Yeon Choi ◽  
Sang Kyu Park ◽  
Cheolhee Won ◽  
Bong-Woo Kim ◽  
...  
Keyword(s):  
Germ Cell ◽  
Cell Fate ◽  
Nuclear Transfer ◽  
Cell Function ◽  
Control Cell ◽  
Donor Cell ◽  
Male Germ Cell ◽  
Cell Group ◽  
Cell Extracts

Recent studies reported that the direct transformation of one differentiated somatic cell type into another is possible. In the present study, we were able to modulate the cell fate of somatic cells to take on male germ cell function by introducing cell extracts derived from porcine testis tissue. Fibroblasts were treated with streptolysin O, which reversibly permeabilises the plasma membrane, and incubated with testis extracts. Our results showed that the testis extracts (TE) could activate expression of male germ cell-specific genes, implying that TE can provide regulatory components required for altering the cell fate of fibroblasts. Male germ cell function was sustained for more than 10 days after the introduction of TE. In addition, a single TE-treated cell was injected directly into the cytoplasm of in vitro-matured porcine oocytes. The rate of blastocyst formation was significantly higher in the TE-treated nuclear donor cell group than in the control cell group. The expression level of Nanog, Sox9 and Eomes was drastically increased when altered cells were used as donor nuclei. Our results suggest that TE can be used to alter the cell fate of fibroblasts to express male germ cell function and improve the developmental efficiency of the nuclear transfer porcine embryos.

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