Two mechanosensitive channel homologs influence division ring placement in Arabidopsis chloroplasts

Plant Cell. 2011 Aug;23(8):2939-49. doi: 10.1105/tpc.111.088112. Epub 2011 Aug 2.

Abstract

Chloroplasts must divide repeatedly to maintain their population during plant growth and development. A number of proteins required for chloroplast division have been identified, and the functional relationships between them are beginning to be elucidated. In both chloroplasts and bacteria, the future site of division is specified by placement of the Filamentous temperature sensitive Z (FtsZ) ring, and the Min system serves to restrict FtsZ ring formation to mid-chloroplast or mid-cell. How the Min system is regulated in response to environmental and developmental factors is largely unstudied. Here, we investigated the role in chloroplast division played by two Arabidopsis thaliana homologs of the bacterial mechanosensitive (MS) channel MscS: MscS-Like 2 (MSL2) and MSL3. Immunofluorescence microscopy and live imaging approaches demonstrated that msl2 msl3 double mutants have enlarged chloroplasts containing multiple FtsZ rings. Genetic analyses indicate that MSL2, MSL3, and components of the Min system function in the same pathway to regulate chloroplast size and FtsZ ring formation. In addition, an Escherichia coli strain lacking MS channels also showed aberrant FtsZ ring assembly. These results establish MS channels as components of the chloroplast division machinery and suggest that their role is evolutionarily conserved.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Arabidopsis / genetics
  • Arabidopsis / physiology*
  • Arabidopsis / ultrastructure
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism*
  • Chloroplasts / metabolism*
  • Chloroplasts / ultrastructure
  • Escherichia coli / genetics
  • Escherichia coli / metabolism
  • Gene Expression Regulation, Plant / physiology
  • Ion Channels / genetics
  • Ion Channels / metabolism*
  • Mutation
  • Phenotype
  • Plant Leaves / genetics
  • Plant Leaves / physiology
  • Plant Leaves / ultrastructure
  • Plants, Genetically Modified
  • RNA, Messenger / genetics
  • RNA, Plant / genetics
  • Recombinant Fusion Proteins
  • Two-Hybrid System Techniques

Substances

  • Arabidopsis Proteins
  • FTSZ protein, Arabidopsis
  • Ion Channels
  • MSL2 protein, Arabidopsis
  • MSL3 protein, Arabidopsis
  • RNA, Messenger
  • RNA, Plant
  • Recombinant Fusion Proteins