Figure 1.

Schematic representation of the protein domains possessed by each HD-Zip family. ATHB1, ATHB2, ATHB8, and GLABRA2 were chosen as representative members of the HD-Zip I, II, III and IV families, respectively. N-term, N-terminus consensus; EAR, LxLxL type of ERF-associated amphiphilic repression; HD, Homeodomain; Zip, Leucine zipper; START, steroidogenic acute regulatory protein-related lipid-transfer domain; SAD, Small body size–mothers against decapentaplegic homolog 4 (Smad4) activation domain; MEKHLA, named after the identification of the highly conserved amino acids Met, Glu, Lys, His, Leu, Ala. Adapted from Ariel et al (2007) [6].