Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P20226 (TATA-binding protein)
 1,297 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Calmodulin (CaM) is the principal Ca(2+) receptor protein inside the cell. When activated by Ca(2+), CaM binds and activates target proteins, thus altering the metabolism and physiology of the cell. Under basal conditions, calcium-free CaM binds to other proteins termed CaM-binding proteins. Recently, we described endothelial differentiation-related factor (EDF)-1 as a protein involved in the repression of endothelial cell differentiation (Dragoni, I., Mariotti, M., Consalez, G. G., Soria, M., and Maier, J. A. M. (1998) J. Biol. Chem. 273, 31119-31124). Here we report that (i) EDF-1 binds CaM in vitro and in vivo; (ii) EDF-1 is phosphorylated in vitro and in vivo by protein kinase C; and (iii) EDF-1-CaM interaction is modulated by the concentrations of Ca(2+) and by the phosphorylation of EDF-1 by protein kinase C both in vitro and in vivo. In addition, 12-O-tetradecanoylphorbol-13-acetate treatment of human umbilical vein endothelial cell stimulates the nuclear translocation of EDF-1. On the basis of the high homology of EDF-1 with multiprotein bridging factor-1, a transcriptional coactivator that binds TATA-binding protein (TBP), we also demonstrate that EDF-1 interacts with TBP in vitro and in human endothelial cells. We hypothesize that EDF-1 serves two main functions in endothelial cells as follows: (i) to bind CaM in the cytosol at physiologic concentrations of Ca(2+) and (ii) to act in the nucleus as a transcriptional coactivator through its binding to TBP.
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PMID:Interaction between endothelial differentiation-related factor-1 and calmodulin in vitro and in vivo. 1081 71

Endothelial differentiation-related factor (EDF)-1 is involved in the repression of endothelial cell differentiation and is the first studied calmodulin (CaM)-binding protein in endothelial cells. Here we report that (i) EDF-1 is in vitro and in vivo phosphorylated by protein kinase A (PKA); (ii) EDF-1/CaM interaction is modulated by the phosphorylation of EDF-1 by PKA; (iii) forskolin stimulates nuclear accumulation of EDF-1, and (iv) PKA phosphorylation enhances EDF-1 interaction with the TATA-binding protein. CaM modulates the activity of several enzymes, among which is nitric oxide synthase (NOS). EDF-1, but not phosphorylated EDF-1, inhibits the activity of NOS. Accordingly, we detected an increase in NOS activity in cells that express low amounts of EDF-1. Our results indicate that EDF-1 serves two main functions in endothelial cells: (i) it regulates CaM availability in the cytosol, and (ii) it acts in the nucleus as a transcriptional coactivator.
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PMID:The dual role of endothelial differentiation-related factor-1 in the cytosol and nucleus: modulation by protein kinase A. 1511 53

Tandem affinity purification (TAP) allows for rapid and efficient purification of epitope-tagged protein complexes from crude extracts under native conditions. The method was established in yeast and has been successfully applied to other organisms, including mammals and trypanosomes. However, we found that the original method, which is based on the TAP tag, consisting of a duplicate protein A epitope, a tobacco etch virus protease cleavage site, and the calmodulin-binding peptide (CBP), did not yield enough recovery of transcription factor SNAPc (for small nuclear RNA-activating protein complex) from crude trypanosome extracts for protein identification. Specifically, the calmodulin affinity chromatography step proved to be inefficient. To overcome this problem, we replaced CBP by the protein C epitope (ProtC) and termed this new epitope combination PTP tag. ProtC binds with high affinity to the monoclonal antibody HPC4, which has the unique property of requiring calcium for antigen recognition. Thus, analogous to the calcium-dependent CBP-calmodulin interaction, ProtC-tagged proteins can be released from immobilized HPC4 by a chelator of divalent cations. While this property was retained, epitope substitution improved purification in our experiments by eliminating the inefficiency of calmodulin affinity chromatography and by providing an alternative way of elution using the ProtC peptide in cases where EGTA inactivated protein function. Furthermore, HPC4 allowed highly sensitive and specific detection of ProtC-tagged proteins after protease cleavage. Thus far, we have successfully purified and characterized the U1 small nuclear ribonucleoprotein particle, the transcription factor complex TATA-binding protein related factor 4 (TRF4)/SNAPc/transcription factor IIA (TFIIA), and RNA polymerase I of Trypanosoma brucei.
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PMID:Highly efficient tandem affinity purification of trypanosome protein complexes based on a novel epitope combination. 1627 61