Zinc transport via ZNT5-6 and ZNT7 is critical for cell surface glycosylphosphatidylinositol-anchored protein expression

Takumi Wagatsuma, Keiko Shimotsuma, Akiko Sogo, Risa Sato, Naoya Kubo, Sachiko Ueda, Yasuo Uchida, Masato Kinoshita, Taiho Kambe

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


Glycosylphosphatidylinositol (GPI)-anchored proteins play crucial roles in various enzyme activities, cell signaling and adhesion, and immune responses. While the molecular mechanism underlying GPI-anchored protein biosynthesis has been well studied, the role of zinc transport in this process has not yet been elucidated. Zn transporter (ZNT) proteins mobilize cytosolic zinc to the extracellular space and to intracellular compartments. Here, we report that the early secretory pathway ZNTs (ZNT5–ZNT6 heterodimers [ZNT5-6] and ZNT7–ZNT7 homodimers [ZNT7]), which supply zinc to the lumen of the early secretory pathway compartments are essential for GPI-anchored protein expression on the cell surface. We show, using overexpression and gene disruption/re-expression strategies in cultured human cells, that loss of ZNT5-6 and ZNT7 zinc transport functions results in significant reduction in GPI-anchored protein levels similar to that in mutant cells lacking phosphatidylinositol glycan anchor biosynthesis (PIG) genes. Furthermore, medaka fish with disrupted Znt5 and Znt7 genes show touch-insensitive phenotypes similar to zebrafish Pig mutants. These findings provide a previously unappreciated insight into the regulation of GPI-anchored protein expression and protein quality control in the early secretory pathway.

Original languageEnglish
Article number102011
JournalJournal of Biological Chemistry
Issue number6
Publication statusPublished - 2022 Jun


  • ER quality control
  • ZNT
  • cell surface
  • early secretory pathway
  • ectoenzyme
  • glycosylphosphatidylinositol (GPI anchor)
  • phosphatidylinositol glycan anchor biosynthesis (PIG)
  • transporter
  • zinc

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology


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