scholarly journals Phosphorylation of ORF1p is required for L1 retrotransposition

2015 ◽  
Vol 112 (14) ◽  
pp. 4298-4303 ◽  
Author(s):  
Pamela R. Cook ◽  
Charles E. Jones ◽  
Anthony V. Furano
Keyword(s):  
Specific Interaction ◽  
Biochemical Property ◽  
Prolyl Isomerase ◽  
Peptidyl Prolyl Isomerase ◽  
Cyclin Dependent Kinases ◽  
Host Interaction ◽  
Mitogen Activated Protein ◽  
Regulatory Cascades ◽  
Substrate Conformation

Although members of the L1 (LINE-1) clade of non-LTR retrotransposons can be deleterious, the L1 clade has remained active in most mammals for ∼100 million years and generated almost 40% of the human genome. The details of L1–host interaction are largely unknown, however. Here we report that L1 activity requires phosphorylation of the protein encoded by the L1 ORF1 (ORF1p). Critical phospho-acceptor residues (two serines and two threonines) reside in four conserved proline-directed protein kinase (PDPK) target sites. The PDPK family includes mitogen-activated protein kinases and cyclin-dependent kinases. Mutation of any PDPK phospho-acceptor inhibits L1 retrotransposition. The phosphomimetic aspartic acid can restore activity at the two serine sites, but not at either threonine site, where it is strongly inhibitory. ORF1p also contains conserved PDPK docking sites, which promote specific interaction of PDPKs with their targets. As expected, mutations in these sites also inhibit L1 activity. PDPK mutations in ORF1p that inactivate L1 have no significant effect on the ability of ORF1p to anneal RNA in vitro, an important biochemical property of the protein. We show that phosphorylated PDPK sites in ORF1p are required for an interaction with the peptidyl prolyl isomerase 1 (Pin1), a critical component of PDPK-mediated regulation. Pin1 acts via isomerization of proline side chains at phosphorylated PDPK motifs, thereby affecting substrate conformation and activity. Our demonstration that L1 activity is dependent on and integrated with cellular phosphorylation regulatory cascades significantly increases our understanding of interactions between L1 and its host.

scholarly journals Cdk2 and Pin1 negatively regulate the transcriptional corepressor SMRT

2008 ◽  
Vol 183 (1) ◽  
pp. 49-61 ◽  
Author(s):  
Kristopher J. Stanya ◽  
Yu Liu ◽  
Anthony R. Means ◽  
Hung-Ying Kao
Keyword(s):  
Transcriptional Repression ◽  
Mammalian Cells ◽  
Cellular Response ◽  
Thyroid Hormone Receptor ◽  
Signaling Cascade ◽  
Phosphorylation Sites ◽  
Transcriptional Corepressor ◽  
Prolyl Isomerase ◽  
Peptidyl Prolyl Isomerase

Silencing mediator for retinoic acid and thyroid hormone receptor (SMRT) is a transcriptional corepressor that participates in diverse signaling pathways and human diseases. However, regulation of SMRT stability remains largely unexplored. We show that the peptidyl-prolyl isomerase Pin1 interacts with SMRT both in vitro and in mammalian cells. This interaction requires the WW domain of Pin1 and SMRT phosphorylation. Pin1 regulates SMRT protein stability, thereby affecting SMRT-dependent transcriptional repression. SMRT phosphorylation at multiple sites is required for Pin1 interaction, and these sites can be phosphorylated by Cdk2, which interacts with SMRT. Cdk2-mediated phosphorylation of SMRT is required for Pin1 binding and decreases SMRT stability, whereas mutation of these phosphorylation sites abrogates Pin1 binding and stabilizes SMRT. Finally, decreases in SMRT stability occur in response to the activation of Her2/Neu/ErbB2, and this receptor functions upstream of both Pin1 and Cdk2 in the signaling cascade that regulates SMRT stability and cellular response to tamoxifen.

scholarly journals Cyclophilin D regulates necrosis, but not apoptosis, of murine eosinophils

2016 ◽  
Vol 310 (8) ◽  
pp. G609-G617 ◽  
Author(s):  
Xiang Zhu ◽  
Simon P. Hogan ◽  
Jeffery D. Molkentin ◽  
Nives Zimmermann
Keyword(s):  
Apoptotic Cell ◽  
Cyclophilin D ◽  
Prolyl Isomerase ◽  
Peptidyl Prolyl Isomerase ◽  
Significant Difference ◽  
Insight Into ◽  
Colitis Model ◽  
Eosinophil Degranulation

Eosinophil degranulation and clusters of free extracellular granules are frequently observed in diverse diseases, including atopic dermatitis, nasal polyposis, and eosinophilic esophagitis. Whether these intact granules are released by necrosis or a biochemically mediated cytolysis remains unknown. Recently, a peptidyl-prolyl isomerase located within the mitochondrial matrix, cyclophilin D (PPIF), was shown to regulate necrotic, but not apoptotic, cell death in vitro in fibroblasts, hepatocytes, and cardiomyocytes. Whether cyclophilin D regulates necrosis in hematopoietic cells such as eosinophils remains unknown. We used PPIF-deficient ( Ppif−/−) mice to test whether cyclophilin D is required for regulating eosinophil necrosis. PPIF deficiency did not affect eosinophil development or maturation at baseline. After in vitro ionomycin or H2O2 treatment, Ppif−/− eosinophils were significantly protected from Ca2+ overload- or oxidative stress-induced necrosis. Additionally, Ppif−/− eosinophils demonstrated significantly decreased necrosis, but not apoptosis, in response to Siglec-F cross-linking, a stimulus associated with eosinophil-mediated processes in vitro and in vivo. When treated with apoptosis inducers, Ppif+/+ and Ppif−/− eosinophils exhibited no significant difference in apoptosis or secondary necrosis. Finally, in a dextran sodium sulfate-induced colitis model, although levels of colitogenic cytokines and eosinophil-selective chemokines were comparable between Ppif+/+ and Ppif−/− mice, the latter exhibited decreased clinical outcomes. This correlated with significantly reduced eosinophil cytolysis in the colon. Collectively, our present studies demonstrate that murine eosinophil necrosis is regulated in vitro and in vivo by cyclophilin D, at least in part, thus providing new insight into the mechanism of eosinophil necrosis and release of free extracellular granules in eosinophil-associated diseases.

scholarly journals The Peptidyl-Prolyl Isomerase Activity of SlyD Is Not Required for Maturation of Escherichia coli Hydrogenase

2007 ◽  
Vol 189 (21) ◽  
pp. 7942-7944 ◽  
Author(s):  
Jie Wei Zhang ◽  
Michael R. Leach ◽  
Deborah B. Zamble
Keyword(s):  
Escherichia Coli ◽  
Metal Cluster ◽  
The Other ◽  
Prolyl Isomerase ◽  
Ppiase Activity ◽  
Peptidyl Prolyl Isomerase ◽  
Isomerase Activity ◽  
Hydrogenase Enzymes

ABSTRACT Escherichia coli SlyD, which is involved in the biosynthesis of the metal cluster in the [NiFe]-hydrogenase enzymes, exhibits several activities including that of a peptidyl-prolyl isomerase (PPIase). Mutations that result in deficient PPIase activity do not produce corresponding decreases in the other activities of SlyD in vitro or in hydrogenase production levels in vivo.

Effect of FKBP65, a putative elastin chaperone, on the coacervation of tropoelastin in vitro

2010 ◽  
Vol 88 (6) ◽  
pp. 917-925 ◽  
Author(s):  
Kevin L.Y. Cheung ◽  
Matthew Bates ◽  
Vettai S. Ananthanarayanan
Keyword(s):  
Self Assembly ◽  
Secretory Pathway ◽  
Molar Ratio ◽  
Prolyl Isomerase ◽  
Ppiase Activity ◽  
Peptidyl Prolyl Isomerase ◽  
Maturation Stages ◽  
Turbidimetric Assay

FKBP65 is a protein of the endoplasmic reticulum that is relatively abundant in elastin-producing cells and is associated with tropoelastin in the secretory pathway. To test an earlier suggestion by Davis and co-workers that FKBP65 could act as an intracellular chaperone for elastin, we obtained recombinant FKBP65 (rFKBP65) by expressing it in E. coli and examined its effect on the coacervation characteristics of chicken aorta tropoelastin (TE) using an in vitro turbidimetric assay. Our results reveal that rFKBP65 markedly promotes the initiation of coacervation of TE without significantly affecting the temperature of onset of coacervation. This effect shows saturation at a 1:2 molar ratio of TE to rFKBP65. By contrast, FKBP12, a peptidyl prolyl isomerase, has a negligible effect on TE coacervation. Moreover, the effect of rFKBP65 on TE coacervation is unaffected by the addition of rapamycin, an inhibitor of peptidyl prolyl isomerase (PPIase) activity. These observations rule out the involvement of the PPIase activity of rFKBP65 in modulating the coacervation of TE. Additional experiments using a polypeptide model of TE showed that rFKBP65, while promoting coacervation, may retard the maturation of this model polypeptide into larger aggregates. Based on these results, we suggest that FKBP65 may act as an elastin chaperone in vivo by controlling both the coacervation and the maturation stages of its self-assembly into fibrils.

scholarly journals Association of polo-like kinase with α-, β- and γ-tubulins in a stable complex

1999 ◽  
Vol 339 (2) ◽  
pp. 435-442 ◽  
Author(s):  
Yang FENG ◽  
David R. HODGE ◽  
Giuseppe PALMIERI ◽  
Dan L. CHASE ◽  
Dan L. LONGO ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Specific Interaction ◽  
Gel Filtration ◽  
Mitotic Cell ◽  
Kinase Domain ◽  
Stable Complex ◽  
Peptidyl Prolyl Isomerase ◽  
High Concentrations

The polo-like kinase (Plk) family has been shown to have an important role in the regulation of the cell-division cycle, especially in organization of the spindle structure, in species from fungi to humans. Recent reports have demonstrated that in mammalian cells Plk is associated with components of the anaphase-promoting complex and a peptidyl-prolyl isomerase, Pin1. To characterize a putative Plk-containing complex, we fractionated mitotic cell lysates on a gel-filtration column. The Plk complex was eluted from the column at molecular sizes ranging from 669 to 2500 kDa in the presence of detergent and high concentrations of salt. Specific associations of Plk with α-, β- and γ-tubulins in both interphase and mitotic cells were shown by reciprocal immunoprecipitations and immunoblottings and were independent of the microtubule polymerization state, whereas binding assays in vitro indicated that Plk interacts with α- and β-tubulins directly. In addition, mitotic Plk was able to phosphorylate associated tubulins in vitro. Finally, we show that the kinase domain of the Plk molecule is both required and sufficient for its binding to tubulins in vivo. The specific interaction between Plk and tubulins might provide a molecular basis for the physiological functions of Plk in regulating the cell cycle, particularly in establishing the normal bipolar spindle.

scholarly journals Peptidyl-Prolyl Isomerase 1 (Pin1) Serves as a Coactivator of Steroid Receptor by Regulating the Activity of Phosphorylated Steroid Receptor Coactivator 3 (SRC-3/AIB1)

2005 ◽  
Vol 25 (21) ◽  
pp. 9687-9699 ◽  
Author(s):  
Ping Yi ◽  
Ray-Chang Wu ◽  
Joshua Sandquist ◽  
Jiemin Wong ◽  
Sophia Y. Tsai ◽  
...  
Keyword(s):  
Conformational Changes ◽  
Intracellular Signaling ◽  
Steroid Receptors ◽  
Steroid Receptor ◽  
Dependent Manner ◽  
Prolyl Isomerase ◽  
Peptidyl Prolyl Isomerase ◽  
Steroid Receptor Coactivator

ABSTRACT Steroid receptor coactivator 3 (SRC-3/AIB1) interacts with steroid receptors in a ligand-dependent manner to activate receptor-mediated transcription. A number of intracellular signaling pathways initiated by growth factors and hormones induce phosphorylation of SRC-3, regulating its function and contributing to its oncogenic potential. However, the range of mechanisms by which phosphorylation affects coactivator function remains largely undefined. We demonstrate here that peptidyl-prolyl isomerase 1 (Pin1), which catalyzes the isomerization of phosphorylated Ser/Thr-Pro peptide bonds to induce conformational changes of its target proteins, interacts selectively with phosphorylated SRC-3. In addition, Pin1 and SRC-3 activate nuclear-receptor-regulated transcription synergistically. Depletion of Pin1 by small interfering RNA (siRNA) reduces hormone-dependent transcription from both transfected reporters and an endogenous steroid receptor target gene. We present evidence that Pin1 modulates interactions between SRC-3 and CBP/p300. The interaction is enhanced in vitro and in vivo by Pin1 and diminished when cellular Pin1 is reduced by siRNA or in stable Pin1-depleted cell lines. Depletion of Pin1 in MCF-7 human breast cancer cells reduces the endogenous estrogen-dependent recruitment of p300 to the promoters of estrogen receptor-dependent genes. Pin1 overexpression enhanced SRC-3 cellular turnover, and depletion of Pin1 stabilized SRC-3. Our results suggest that Pin1 functions as a transcriptional coactivator of nuclear receptors by modulating SRC-3 coactivator protein-protein complex formation and ultimately by also promoting the turnover of the activated SRC-3 oncoprotein.

scholarly journals TWISTED DWARF1, a Unique Plasma Membrane-anchored Immunophilin-like Protein, Interacts with Arabidopsis Multidrug Resistance-like Transporters AtPGP1 and AtPGP19

2003 ◽  
Vol 14 (10) ◽  
pp. 4238-4249 ◽  
Author(s):  
Markus Geisler ◽  
H. Üner Kolukisaoglu ◽  
Rodolphe Bouchard ◽  
Karla Billion ◽  
Joachim Berger ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Protein Interaction ◽  
Single Gene ◽  
Integral Membrane Protein ◽  
Prolyl Isomerase ◽  
Ppiase Activity ◽  
Peptidyl Prolyl Isomerase ◽  
Protein Protein Interaction ◽  
Cdna Sequences

Null-mutations of the Arabidopsis FKBP-like immunophilin TWISTED DWARF1 (TWD1) gene cause a pleiotropic phenotype characterized by reduction of cell elongation and disorientated growth of all plant organs. Heterologously expressed TWD1 does not exhibit cis-trans-peptidylprolyl isomerase (PPIase) activity and does not complement yeast FKBP12 mutants, suggesting that TWD1 acts indirectly via protein-protein interaction. Yeast two-hybrid protein interaction screens with TWD1 identified cDNA sequences that encode the C-terminal domain of Arabidopsis multidrugresistance-like ABC transporter AtPGP1. This interaction was verified in vitro. Mapping of protein interaction domains shows that AtPGP1 surprisingly binds to the N-terminus of TWD1 harboring the cis-trans peptidyl-prolyl isomerase-like domain and not to the tetratrico-peptide repeat domain, which has been shown to mediate protein-protein interaction. Unlike all other FKBPs, TWD1 is shown to be an integral membrane protein that colocalizes with its interacting partner AtPGP1 on the plasma membrane. TWD1 also interacts with AtPGP19 (AtMDR1), the closest homologue of AtPGP1. The single gene mutation twd1-1 and double atpgp1-1/atpgp19-1 (atmdr1-1) mutants exhibit similar phenotypes including epinastic growth, reduced inflorescence size, and reduced polar auxin transport, suggesting that a functional TWD1-AtPGP1/AtPGP19 complex is required for proper plant development.

The peptidyl-prolyl isomerase SlrA contributes to virulence and adherence of Streptococcus pneumoniae

Pneumologie ◽  
2006 ◽  
Vol 60 (02) ◽  
Author(s):  
S Hammerschmidt ◽  
PV Adrian ◽  
C Albert ◽  
S Estevão ◽  
T Hoogenboezem ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Prolyl Isomerase ◽  
Peptidyl Prolyl Isomerase

Correlation between in vitro and in vivo Data of Radiolabeled Peptide for Tumor Targeting

2019 ◽  
Vol 19 (12) ◽  
pp. 950-960
Author(s):  
Soghra Farzipour ◽  
Seyed Jalal Hosseinimehr
Keyword(s):  
Tumor Targeting ◽  
Single Photon ◽  
Specific Binding ◽  
Specific Interaction ◽  
Photon Emission ◽  
Emission Computed Tomography ◽  
Mixed Effect ◽  
Radiolabeled Peptides

Tumor-targeting peptides have been generally developed for the overexpression of tumor specific receptors in cancer cells. The use of specific radiolabeled peptide allows tumor visualization by single photon emission computed tomography (SPECT) and positron emission tomography (PET) tools. The high affinity and specific binding of radiolabeled peptide are focusing on tumoral receptors. The character of the peptide itself, in particular, its complex molecular structure and behaviors influence on its specific interaction with receptors which are overexpressed in tumor. This review summarizes various strategies which are applied for the expansion of radiolabeled peptides for tumor targeting based on in vitro and in vivo specific tumor data and then their data were compared to find any correlation between these experiments. With a careful look at previous studies, it can be found that in vitro unblock-block ratio was unable to correlate the tumor to muscle ratio and the success of radiolabeled peptide for in vivo tumor targeting. The introduction of modifiers’ approaches, nature of peptides, and type of chelators and co-ligands have mixed effect on the in vitro and in vivo specificity of radiolabeled peptides.

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