UV-A light regulation of arylalkylamine N-acetyltransferase activity in the chick pineal gland: role of cAMP and proteasomal proteolysis
Article first published online: 22 JUL 2005
Journal of Pineal Research
Volume 39, Issue 4, pages 419–424, November 2005
How to Cite
Rosiak, J., Michael Iuvone, P. and Zawilska, J. B. (2005), UV-A light regulation of arylalkylamine N-acetyltransferase activity in the chick pineal gland: role of cAMP and proteasomal proteolysis. Journal of Pineal Research, 39: 419–424. doi: 10.1111/j.1600-079X.2005.00267.x
- Issue published online: 22 JUL 2005
- Article first published online: 22 JUL 2005
- Received April 7, 2005; accepted June 14, 2005.
- pineal gland;
- proteasomal proteolysis;
- serotonin N-acetyltransferase;
Abstract: Acute exposure of dark-adapted, cultured chick pineal glands to UV-A light significantly decreased the tissue cAMP concentration and the activity of arylalkylamine N-acetyltransferase (AANAT), the penultimate and key regulatory enzyme in the melatonin biosynthetic pathway. The magnitude of these changes was dependent on the duration of UV-A exposure. The UV-A light-evoked decline in pineal AANAT activity was blocked by cAMP protagonists (forskolin and dibutyryl-cAMP) and by inhibitors of the proteasomal degradation pathway (MG-132, proteasome inhibitor I, and lactacystin). These results indicate that the chick pineal gland is directly sensitive to UV-A light. By analogy to white light, the suppressive action of UV-A radiation on AANAT activity in the chick pineal gland involves changes in the tissue cAMP level and enhanced proteasomal proteolysis.