{PDOC51297} {PS51297; K_BOX} {BEGIN} ************************ * K-box domain profile * ************************ MADS genes in plants encode key developmental regulators of vegetative and reproductive development. The majority of the plant MADS proteins share a stereotypical MIKC structure. It comprises (from N- to C-terminal) an N- terminal domain, which is, however, present only in a minority of proteins; a MADS domain (see ), which is the major determinant of DNA-binding but which also performs dimerization and accessory factor binding functions; a weakly conserved intervening (I) domain, which constitutes a key molecular determinant for the selective formation of DNA-binding dimers; a keratin-like (K-box) domain, which promotes protein dimerization; and a C-terminal (C) domain, which is involved in transcriptional activation or in the formation of ternary or quaternary protein complexes. The 80-amino acid K-box domain was originally identified as a region with low but significant similarity to a region of keratin, which is part of the coiled-coil sequence constituting the central rod-shaped domain of keratin [1-3]. The K-box protein-protein interaction domain which mediates heterodimerization of MIKC-type MADS proteins contains several heptad repeats in which the first and the fourth positions are occupied by hydrophobic amino acids suggesting that the K-box domain forms three amphipathic alpha-helices referred to as K1, K2, and K3 [3]. The profile we developed covers the entire K-box domain. -Sequences known to belong to this class detected by the profile: ALL. -Other sequence(s) detected in Swiss-Prot: NONE. -Last update: February 2007 / First entry. [ 1] Alvarez-Buylla E.R., Pelaz S., Liljegren S.J., Gold S.E., Burgeff C., Ditta G.S., Ribas de Pouplana L., Martinez-Castilla L., Yanofsky M.F. "An ancestral MADS-box gene duplication occurred before the divergence of plants and animals." Proc. Natl. Acad. Sci. U.S.A. 97:5328-5333(2000). PubMed=10805792 [ 2] Henschel K., Kofuji R., Hasebe M., Saedler H., Muenster T., Theissen G. "Two ancient classes of MIKC-type MADS-box genes are present in the moss Physcomitrella patens." Mol. Biol. Evol. 19:801-814(2002). PubMed=12032236 [ 3] Yang Y., Fanning L., Jack T. "The K domain mediates heterodimerization of the Arabidopsis floral organ identity proteins, APETALA3 and PISTILLATA." Plant J. 33:47-59(2003). PubMed=12943540 -------------------------------------------------------------------------------- PROSITE is copyrighted by the SIB Swiss Institute of Bioinformatics and distributed under the Creative Commons Attribution-NonCommercial-NoDerivatives (CC BY-NC-ND 4.0) License, see https://prosite.expasy.org/prosite_license.html -------------------------------------------------------------------------------- {END}