Plant Molecular Biology

, Volume 78, Issue 3, pp 211–222

The Arabidopsis calmodulin-like proteins AtCML30 and AtCML3 are targeted to mitochondria and peroxisomes, respectively

  • Fatima Chigri
  • Sandra Flosdorff
  • Sahra Pilz
  • Eva Kölle
  • Esther Dolze
  • Christine Gietl
  • Ute C. Vothknecht
Article

DOI: 10.1007/s11103-011-9856-z

Cite this article as:
Chigri, F., Flosdorff, S., Pilz, S. et al. Plant Mol Biol (2012) 78: 211. doi:10.1007/s11103-011-9856-z

Abstract

Calmodulin (CaM) is a ubiquitous sensor/transducer of calcium signals in eukaryotic organisms. While CaM mediated calcium regulation of cytosolic processes is well established, there is growing evidence for the inclusion of organelles such as chloroplasts, mitochondria and peroxisomes into the calcium/calmodulin regulation network. A number of CaM-binding proteins have been identified in these organelles and processes such as protein import into chloroplasts and mitochondria have been shown to be governed by CaM regulation. What have been missing to date are the mediators of this regulation since no CaM or calmodulin-like protein (CML) has been identified in any of these organelles. Here we show that two Arabidopsis CMLs, AtCML3 and AtCML30, are localized in peroxisomes and mitochondria, respectively. AtCML3 is targeted via an unusual C-terminal PTS1-like tripeptide while AtCML30 utilizes an N-terminal, non-cleavable transit peptide. Both proteins possess the typical structure of CaMs, with two pairs of EF-hand motifs separated by a short linker domain. They furthermore display common characteristics, such as calcium-dependent alteration of gel mobility and calcium-dependent exposure of a hydrophobic surface. This indicates that they can function in a similar manner as canonical CaMs. The presence of close homologues to AtCML3 and AtCML30 in other plants further indicates that organellar targeting of these CMLs is not a specific feature of Arabidopsis. The identification of peroxisomal and mitochondrial CMLs is an important step in the understanding how these organelles are integrated into the cellular calcium/calmodulin signaling pathways.

Keywords

Calcium regulationCalmodulin-like proteinsPlant mitochondriaPeroxisomes

Supplementary material

11103_2011_9856_MOESM1_ESM.pdf (590 kb)
Supplementary material 1 (PDF 590 kb)
11103_2011_9856_MOESM2_ESM.pdf (262 kb)
Supplementary material 2 (PDF 262 kb)

Copyright information

© Springer Science+Business Media B.V. 2011

Authors and Affiliations

  • Fatima Chigri
    • 1
  • Sandra Flosdorff
    • 2
  • Sahra Pilz
    • 2
  • Eva Kölle
    • 2
  • Esther Dolze
    • 3
  • Christine Gietl
    • 3
  • Ute C. Vothknecht
    • 1
    • 2
  1. 1.Department of Biology of the LMU MunichCenter for Integrated Protein Science (Munich)MartinsriedGermany
  2. 2.Department of Biology ILMU MunichMartinsriedGermany
  3. 3.Lehrstuhl für BotanikTU Munich, Wissenschaftszentrum WeihenstephanFreisingGermany