부산대학교 도서관

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.yexcr.2005.07.032 Byline: Martin Liden, Kristian Tryggvason, Ulf Eriksson Keywords: Retinol; Retinol dehydrogenase; Metabolism; ER; Retention Abbreviations: CRAD1, cis-retinol/androgen dehydrogenase 1; RA, retinoic acid; RDH, retinol dehydrogenase; SLO, streptolysin O Abstract: Retinoic acid is generated from retinol (vitamin A) by the sequential actions of two different classes of enzymes, retinol dehydrogenases and retinal dehydrogenases. Several enzymes implicated in this process have been identified and characterized in vitro. However, our understanding of the cell biological function and regulation of this process is limited. To get further knowledge regarding the regulation of RA biosynthesis, we have determined possible regulatory mechanisms at the transcriptional and post-transcriptional levels for the prototypic microsomal retinol dehydrogenase cis-retinol/androgen dehydrogenase 1 (CRAD1). We note that the expression and stability of the enzyme are only moderately controlled by the retinoid status. Instead, we find that the cytosolic tail dramatically affects the activity of the enzyme, and we have mapped the structural elements required for ER retention and in vivo functional activity, respectively. Although inactive tail-deletion mutants display an abnormal subcellular localization, restoration of ER localization per se is not sufficient for enzymatic activity suggesting that additional trans-acting components interacting with, or modifying, the cytosolic tail are required for controlling the activity of the enzyme in vivo. Author Affiliation: Ludwig Institute for Cancer Research, Stockholm Branch, Box 240, S-17177 Stockholm, Sweden Article History: Received 3 June 2005; Revised 27 July 2005; Accepted 27 July 2005