TITLE	Characterization of a novel Arabidopsis protein family AtMAPR homologous to 25-Dx/IZAg/Hpr6.6 proteins
AUTHOR	Ai-Ling KAO Department of Biochemical Science and Technology and Institute of Microbiology and Biochemistry, National Taiwan University, No. 1, Section 4, Roosevelt Road, Taipei, Taiwan, ROC Tsz-Yin CHANG Department of Biochemical Science and Technology and Institute of Microbiology and Biochemistry, National Taiwan University, No. 1, Section 4, Roosevelt Road, Taipei, Taiwan, ROC Shuo-Hsiu CHANG Department of Biochemical Science and Technology and Institute of Microbiology and Biochemistry, National Taiwan University, No. 1, Section 4, Roosevelt Road, Taipei, Taiwan, ROC Jong-Ching SU Department of Biochemical Science and Technology and Institute of Microbiology and Biochemistry, National Taiwan University, No. 1, Section 4, Roosevelt Road, Taipei, Taiwan, ROC Chien-Chih YANG* Department of Biochemical Science and Technology and Institute of Microbiology and Biochemistry, National Taiwan University, No. 1, Section 4, Roosevelt Road, Taipei, Taiwan, ROC
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ABSTRACT	Four Arabidopsis genes homologous to the membrane-associated progesterone binding protein (MAPR) were identified. MAPRs have previously been isolated from membrane preparations of porcine liver as proteins binding to progesterone. According to sequence alignment, each of the AtMAPRs, except AtMAPR2, was predicted to contain three domains; the N-terminal domain, except that of AtMAPR2, was predicted to accommodate a single transmembrane alpha-helix. A potentially interesting helical wheel motif SPX10FX2Y was found in the transmembrane domain. Proteins that may interact with AtMAPRs were found using the yeast two-hybrid system. AtMAPR2 and AtMAPR5DTM were found to associate with ubiquitin, where ubiquitination was involved in Aux/IAA modification. Sequence alignment indicated that AtMAPRs are distantly related to the Aux/IAA proteins. AtMAPR2 was also found to bind Myb3, a transcription factor that controls the expression of genes for the biosynthesis of phenylpropanoid. These results imply that AtMAPR may be a part of a plant hormone signaling pathway.
KEYWORD	AtMAPR; Non-genomic effect; Pant hormone signaling;
ARTICLE INFO	Botanical Bulletin of Academia Sinica, Volume 46 Number 2 April 2005, page 107-118, 12 pages
PUBLISHER	Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan, Republic of China