The maize Gα gene COMPACT PLANT2 functions in CLAVATA signalling to control shoot meristem size

Nature. 2013 Oct 24;502(7472):555-8. doi: 10.1038/nature12583. Epub 2013 Sep 11.


Shoot growth depends on meristems, pools of stem cells that are maintained by a negative feedback loop between the CLAVATA pathway and the WUSCHEL homeobox gene. CLAVATA signalling involves a secreted peptide, CLAVATA3 (CLV3), and its perception by cell surface leucine-rich repeat (LRR) receptors, including the CLV1 receptor kinase and a LRR receptor-like protein, CLV2 (ref. 4). However, the signalling mechanisms downstream of these receptors are poorly understood, especially for LRR receptor-like proteins, which lack a signalling domain. Here we show that maize COMPACT PLANT2 (CT2) encodes the predicted α-subunit (Gα) of a heterotrimeric GTP binding protein. Maize ct2 phenotypes resemble Arabidopsis thaliana clavata mutants, and genetic, biochemical and functional assays indicate that CT2/Gα transmits a stem-cell-restrictive signal from a CLAVATA LRR receptor, suggesting a new function for Gα signalling in plants. Heterotrimeric GTP-binding proteins are membrane-associated molecular switches that are commonly activated by ligand binding to an associated seven-pass transmembrane (7TM) G-protein-coupled receptor (GPCR). Recent studies have questioned the idea that plant heterotrimeric G proteins interact with canonical GPCRs, and our findings suggest that single pass transmembrane receptors act as GPCRs in plants, challenging the dogma that GPCRs are exclusively 7TM proteins.

Publication types

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

MeSH terms

  • Cloning, Molecular
  • GTP-Binding Protein alpha Subunits / genetics
  • GTP-Binding Protein alpha Subunits / metabolism*
  • Genes, Plant / genetics*
  • Meristem / anatomy & histology*
  • Meristem / metabolism
  • Mutation / genetics
  • Phenotype
  • Plant Proteins / genetics
  • Plant Proteins / metabolism*
  • Proteome / genetics
  • Proteome / metabolism
  • Receptors, G-Protein-Coupled / chemistry
  • Receptors, G-Protein-Coupled / metabolism
  • Signal Transduction*
  • Zea mays / anatomy & histology*
  • Zea mays / genetics*


  • GTP-Binding Protein alpha Subunits
  • Plant Proteins
  • Proteome
  • Receptors, G-Protein-Coupled