Detailed analyses of the crucial functions of Zn transporter proteins in alkaline phosphatase activation

Numerous zinc ectoenzymes are metalated by zinc and activated in the compartments of the early secretory pathway before reaching their destination. Zn transporter (ZNT) proteins located in these compartments are essential for ectoenzyme activation. We have previously reported that ZNT proteins, specifically ZNT5-ZNT6 heterodimers and ZNT7 homodimers, play critical roles in the activation of zinc ectoenzymes, such as alkaline phosphatases (ALPs), by mobilizing cytosolic zinc into these compartments. However, this process remains incompletely understood. Here, using genetically-engineered chicken DT40 cells, we first determined that Zrt/Irt-like protein (ZIP) transporters that are localized to the compartments of the early secretory pathway play only a minor role in the ALP activation process. These transporters included ZIP7, ZIP9, and ZIP13, performing pivotal functions in maintaining cellular homeostasis by effluxing zinc out of the compartments. Next, using purified ALP proteins, we showed that zinc metalation on ALP produced in DT40 cells lacking ZNT5-ZNT6 heterodimers and ZNT7 homodimers is impaired. Finally, by genetically disrupting both ZNT5 and ZNT7 in human HAP1 cells, we directly demonstrated that the tissue-nonspecific ALP-activating functions of both ZNT complexes are conserved in human cells. Furthermore, using mutant HAP1 cells, we uncovered a previously-unrecognized and unique spatial regulation of ZNT5-ZNT6 heterodimer formation, wherein ZNT5 recruits ZNT6 to the Golgi apparatus to form the heterodimeric complex. These findings fill in major gaps in our understanding of the molecular mechanisms underlying zinc ectoenzyme activation in the compartments of the early secretory pathway

エンショウセイ サイトカイン ニ ヨル peroxisome proliferator - activated receptor ガンマ ハツゲン ヨクセイ ト チアゾリジン ユウドウタイ ニ ヨル ソノ ソガイ

京都大学0048新制・課程博士博士(医学)甲第8649号医博第2296号新制||医||754(附属図書館)UT51-2001-A737京都大学大学院医学研究科内科系専攻(主査)教授 清野 裕, 教授 成宮 周, 教授 中尾 一和学位規則第4条第1項該当Doctor of Medical ScienceKyoto UniversityDA

Palladium-Catalyzed Tetraarylation of 5,15-Dialkylporphyrins with Aryl Bromides

Nickel complexes of 5,15-dialkylporphyrins are subjected to palladium-catalyzed direct arylation under the modified Fagnou conditions. The arylation takes place still exclusively at the four less hindered β positions although the meso-nonyl, hexyl, and propyl groups are considered to impose less steric hindrance than the meso-3,5-di-tert-butylphenyl group in the previous report