| First Author | Tountas NA | Year | 2004 |
| Journal | Histochem Cell Biol | Volume | 121 |
| Issue | 4 | Pages | 343-50 |
| PubMed ID | 15083373 | Mgi Jnum | J:306143 |
| Mgi Id | MGI:6708418 | Doi | 10.1007/s00418-004-0642-8 |
| Citation | Tountas NA, et al. (2004) Juxtamembrane localization of the protein phosphatase-1 inhibitor protein PHI-1 in smooth muscle cells. Histochem Cell Biol 121(4):343-50 |
| abstractText | Protein phosphorylation regulates many fundamental processes and protein phosphatase-1 (PP1) is a major phosphatase that determines the levels of Ser/Thr phosphorylation. Regulatory subunits and inhibitor phosphoproteins control PP1 activity. PHI-1 is a member of a family of PP1 inhibitor phosphoproteins that was discovered based on sequence similarity to the known inhibitor CPI-17. To learn more about PHI-1 we determined the tissue distribution of PHI-1 in embryonic and adult tissues, and examined its cellular localization by immunohistochemistry. In the embryo PHI-1 appeared first in the heart at E10, and by E15 it was detected in multiple tissues. Expression in adult tissues was strikingly different, with PHI-1 detected primarily in smooth muscles in the intestine, blood vessels, and male and female genitourinary tracts. PHI-1 also was highly expressed in the endothelial layer of blood vessels. Both PHI-1 and CPI-17 are expressed predominantly in adult smooth muscles. Whereas CPI-17 staining was diffuse PHI-1 was concentrated along the cell membrane in distinct foci, detected by confocal and electron microscopy. The common tissue distribution but different cellular localization of PHI-1 and CPI-17 suggest distinctive physiological roles for these two PP1 inhibitors. |
