Translational and post-translational regulation of mouse cation transport regulator homolog 1.
Cation transport regulator homolog 1 (Chac1) is an endoplasmic reticulum (ER) stress inducible gene that has a function as a γ-glutamyl cyclotransferase involved in the degradation of glutathione. To characterize the translation and stability of Chac1, we found that the Kozak-like sequence present in the 5' untranslated region (5'UTR) of the Chac1 mRNA was responsible for Chac1 translation. In addition, the short form (ΔChac1), which translated from the second ATG codon, was generated in the absence of the 5'UTR. The proteasome pathway predominantly participated in the stability of the Chac1 protein; however, its expression was remarkably up-regulated by co-transfection with ubiquitin genes. Using an immunoprecipitation assay, we revealed that ubiquitin molecule was directly conjugated to Chac1, and that mutated Chac1 with all lysine residues replaced by arginine was also ubiquitinated. Finally, we showed that WT Chac1 but not ΔChac1 reduced the intracellular level of glutathione. Taken together, our results suggest that the Chac1 protein expression is regulated in translational and post-translational fashion due to the Kozak-like sequence in the 5'UTR and the ubiquitin-mediated pathways. The bidirectional roles of ubiquitination in regulating Chac1 stabilization might give us a new insight into understanding the homeostasis of glutathione under pathophysiological conditions.
United Graduate School of Drug Discovery and Medical Information Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan.
Yuki
Y
Nomura
United Graduate School of Drug Discovery and Medical Information Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan.|Department of Chemistry and Biomolecular Science, Faculty of Engineering, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan.
Yoko
Y
Hirata
United Graduate School of Drug Discovery and Medical Information Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan.|Department of Chemistry and Biomolecular Science, Faculty of Engineering, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan.
Kazutoshi
K
Kiuchi
United Graduate School of Drug Discovery and Medical Information Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan.|Department of Chemistry and Biomolecular Science, Faculty of Engineering, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan.
Kentaro
K
Oh-Hashi
D020121:5' Untranslated Regions; D000818:Animals; D059865:Endoplasmic Reticulum Stress; D005786:Gene Expression Regulation; D005978:Glutathione / Q000378:metabolism*; D057809:HEK293 Cells; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D051379:Mice; D011401:Promoter Regions, Genetic; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D014176:Protein Biosynthesis; D011499:Protein Processing, Post-Translational; D055550:Protein Stability; D012333:RNA, Messenger / Q000235:genetics; D025801:Ubiquitin / Q000378:metabolism*; D054875:Ubiquitination; D005722:gamma-Glutamylcyclotransferase
D020121:5' Untranslated Regions; D047908:Intracellular Signaling Peptides and Proteins; D012333:RNA, Messenger; D025801:Ubiquitin; D046988:Proteasome Endopeptidase Complex; C586183:Chac1 protein, mouse; D005722:gamma-Glutamylcyclotransferase; D005978:Glutathione