Potassium and the K+/H+ Exchanger Kha1p Promote Binding of Copper to ApoFet3p Multi-copper Ferroxidase

作者：Wu, Xiaobin; Kim, Heejeong; Seravalli, Javier; Barycki, Joseph J.; Hart, P. John; Gohara, David W.; Di Cera, Enrico; Jung, Won Hee; Kosman, Daniel J.; Lee, Jaekwon^*

来源：JOURNAL OF BIOLOGICAL CHEMISTRY, 2016, 291(18): 9796-9806.

DOI：10.1074/jbc.M115.700500

• MULTICOPPER OXIDASE FET3P
• UNFOLDED PROTEIN RESPONSE
• VACUOLAR H+-ATPASE
• SACCHAROMYCES-CEREVISIAE
• TRANSCRIPTION FACTOR
• CHLORIDE CHANNELS
• GENE DELETION
• DNA-BINDING
• YEAST
• IRON

Acquisition and distribution of metal ions support a number of biological processes. Here we show that respiratory growth of and iron acquisition by the yeast Saccharomyces cerevisiae relies on potassium (K+) compartmentalization to the trans-Golgi network via Kha1p, a K+/H+ exchanger. K+ in the trans-Golgi network facilitates binding of copper to the Fet3p multi-copper ferroxidase. The effect of K+ is not dependent on stable binding with Fet3p or alteration of the characteristics of the secretory pathway. The data suggest that K+ acts as a chemical factor in Fet3p maturation, a role similar to that of cations in folding of nucleic acids. Up-regulation of KHA1 gene in response to iron limitation via iron-specific transcription factors indicates that K+ compartmentalization is linked to cellular iron homeostasis. Our study reveals a novel functional role of K+ in the binding of copper to apoFet3p and identifies a K+/H+ exchanger at the secretory pathway as a new molecular factor associated with iron uptake in yeast.

• 出版日期2016-4-29
• 单位上海师范大学