InterPro domain: IPR005333

The TCP transcription factor family was named after: teosinte branched 1 (tb1, Zea mays (Maize)) [ 1 ], cycloidea (cyc) (Antirrhinum majus) (Garden snapdragon) [ 2 ] and PCF in rice (Oryza sativa) [ 3 , 4 ]. The TCP proteins code for structurally related proteins implicated in the evolution of key morphological traits [ 5 ]. However, the biochemical function of CYC and TB1 proteins remains to be demonstrated. One of the conserved regions is predicted to form a non-canonical basic-Helix-Loop-Helix (bHLP) structure. This domain is also found in two rice DNA-binding proteins, PCF1 and PCF2, where it has been shown to be involved in DNA-binding and dimerization.

This family of transcription factors are exclusive to higher plants. They can be divided into two groups, TCP-C and TCP-P, that appear to have separated following an early gene duplication event [ 5 ]. This duplication event may have led to functional divergence and it has been proposed that that the TCP-P subfamily are transcriptional repressors, while the TPC-C subfamily are transcription activators [ 6 ].

1. Arabidopsis Teosinte Branched1-like 1 regulates axillary bud outgrowth and is homologous to monocot Teosinte Branched1. Plant Cell Physiol. 48, 667-77
2. The TCP domain: a motif found in proteins regulating plant growth and development. Plant J. 18, 215-22
3. DNA binding and dimerization specificity and potential targets for the TCP protein family. Plant J. 30, 337-48
4. Skin tests, IgE and rast, nasal provocation test. Proc. Natl. Acad. Sci. U.S.A. 33, 572-81
5. TCP transcription factors predate the emergence of land plants. null 65, 23-33
6. Arabidopsis TCP20 links regulation of growth and cell division control pathways. J. Mol. Evol. 102, 12978-83