Identification of evolutionarily conserved amino acid residues in homeodomain of KNOX proteins for intercellular trafficking

Plant Signal Behav. 2014;9(3):e28355. doi: 10.4161/psb.28355. Epub 2014 Feb 28.

Abstract

Maize knotted (KN1) homeodomain (HD) protein is a well-known mobile transcription factor crucial for stem cell maintenance. Recent studies have revealed that the trihelical HD of knotted1-like homeobox (KNOX) proteins is necessary and sufficient for selective cell-to-cell trafficking. Also, the efficient trafficking ability for HD is likely to be acquired during the evolution of early nonvascular land plants. Here, using the point-mutated HD of KN1 and shoot meristemless (STM) in the trichome rescue system, together with molecular structure modeling, we have found the evolutionarily conserved amino acid residues, such as arginine in helix α1 and leucine in helix α3, which are essential for intercellular trafficking. Our studies provided important clues for the 3-dimensional protein structure required for cell-to-cell movement of non-cell-autonomous transcription factors.

Keywords: homeodomain; intercellular protein trafficking; non-cell-autonomous; plasmodesmata; transcription factor.

Publication types

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

MeSH terms

  • Amino Acid Sequence
  • Conserved Sequence
  • Homeodomain Proteins / chemistry*
  • Homeodomain Proteins / metabolism
  • Molecular Sequence Data
  • Plant Proteins / chemistry*
  • Plant Proteins / metabolism
  • Protein Transport
  • Zea mays / chemistry*
  • Zea mays / metabolism

Substances

  • Homeodomain Proteins
  • Plant Proteins