Determination of structural regions important for Ca 2+ uptake activity in arabidopsis MCA1 and MCA2 expressed in yeast

Masataka Nakano, Kazuko Iida, Hiroshi Nyunoya, Hidetoshi Iida

Research output: Contribution to journalArticle

25 Citations (Scopus)

Abstract

MCA1 is a plasma membrane protein that correlates Ca 2+ influx and mechanosensing in Arabidopsis. MCA2 is a paralog of MCA1, and both share 72.7 amino acid sequence identity and several common structural features, including putative transmembrane (TM) segments, an EF hand-like region in the N-terminal half, a coiled-coil motif in the middle and a PLAC8 motif in the C-terminal half. To determine structural regions important for Ca 2+ uptake activity, the activity of truncated forms of MCA1 and MCA2 was assessed using yeast expression assays. The N-terminal half of MCA1 with a coiled-coil motif (MCA1 1-237) did not have Ca 2+ uptake activity, while MCA2 1-237 did. The N-terminal half of MCA1 without the coiled-coil motif (MCA1 1-185) showed Ca 2+ uptake activity, as did MCA2 1-186. Both MCA1 1-173 and MCA2 1-173 having the EF hand-like region had Ca 2+ uptake activity. Deletion of a putative TM segment (Ile11-Ala33) and the Asp21 to asparagine mutation in MCA1 and MCA2 abolished Ca 2+ uptake activity. Finally, MCA1 173-421 and MCA2 173-416 lacking the N-terminal half had no Ca 2+ uptake activity. These results suggest that the N-terminal half of both proteins with the EF hand-like region is necessary and sufficient for Ca 2+ uptake and that the coiled-coil motif regulates MCA1 negatively and MCA2 positively.

Original languageEnglish
Pages (from-to)1915-1930
Number of pages16
JournalPlant and Cell Physiology
Volume52
Issue number11
DOIs
Publication statusPublished - 2011 Nov 1
Externally publishedYes

Keywords

  • Arabidopsis thaliana
  • Ca channel
  • Ca transport
  • Heterologous expression
  • Saccharomyces cerevisiae
  • Structure-function relationship

ASJC Scopus subject areas

  • Physiology
  • Plant Science
  • Cell Biology

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