PMID: 9228045 RLIMS-P 2 Check other iTextMine results Issue Report
Title
| 1. | Serine phosphorylation within a concise amino-terminal domain in nuclear respiratory factor 1 enhances DNA binding. |
Abstract
| 2. | Nuclear respiratory factor 1 (NRF-1) is a transcriptional activator that acts on a diverse set of nuclear genes required for mitochondrial respiratory function in mammalian cells. |
| 3. | These genes encode respiratory proteins as well as components of the mitochondrial transcription, replication, and heme biosynthetic machinery. |
| 4. | Here, we establish that NRF-1 is a phosphoprotein in vivo. |
| 5. | Phosphorylation occurs on serine residues within a concise NH2-terminal domain with the major sites of phosphate incorporation at serines 39, 44, 46, 47, and 52. |
| 6. | The in vivo phosphorylation pattern can be approximated in vitro by phosphorylating recombinant NRF-1 with purified casein kinase II. |
| 7. | Phosphate incorporation at the sites utilized in vivo results in a marked stimulation of DNA binding activity which is not observed in mutated proteins lacking these sites. |
| 8. | Pairwise expression of the wild-type protein with each of a series of truncated derivatives in transfected cells results in the formation of a dimer between wild-type and mutant forms demonstrating that a homodimer is the active binding species. |
| 9. | Although NRF-1 can dimerize in the absence of DNA, phosphorylation does not enhance the formation of these dimers. |
| 10. | These findings suggest that phosphorylation results in an intrinsic change in the NRF-1 dimer enhancing its ability to bind DNA. |
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