title: Functional analysis of the Hikeshi-like protein and its interaction with HSP70 in Arabidopsis.
abstract: Heat shock proteins (HSPs) refold damaged proteins and are an essential component of the heat shock response. Previously, the 70 kDa heat shock protein (HSP70) has been reported to translocate into the nucleus in a heat-dependent manner in many organisms. In humans, the heat-induced translocation of HSP70 requires the nuclear carrier protein Hikeshi. In the Arabidopsis genome, only one gene encodes a protein with high homology to Hikeshi, and we named this homolog Hikeshi-like (HKL) protein. In this study, we show that two Arabidopsis HSP70 isoforms accumulate in the nucleus in response to heat shock and that HKL interacts with these HSP70s. Our histochemical analysis revealed that HKL is predominantly expressed in meristematic tissues, suggesting the potential importance of HKL during cell division in Arabidopsis. In addition, we show that HKL regulates HSP70 localization, and HKL overexpression conferred thermotolerance to transgenic Arabidopsis plants. Our results suggest that HKL plays a positive role in the thermotolerance of Arabidopsis plants and cooperatively interacts with HSP70.
authors.affiliation: Laboratory of Plant Molecular Physiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
authors.forename: Shinya
authors.initials: S
authors.lastname: Koizumi
authors.affiliation: Laboratory of Plant Molecular Physiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
authors.forename: Naohiko
authors.initials: N
authors.lastname: Ohama
authors.affiliation: Laboratory of Plant Molecular Physiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
authors.forename: Junya
authors.initials: J
authors.lastname: Mizoi
authors.affiliation: RIKEN Plant Science Center, 1-7-22 Suehiro-cho, Tsurumi, Yokohama, Kanagawa 230-0045, Japan.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Shinozaki
authors.affiliation: Laboratory of Plant Molecular Physiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan. Electronic address: akys@mail.ecc.u-tokyo.ac.jp.
authors.forename: Kazuko
authors.initials: K
authors.lastname: Yamaguchi-Shinozaki
mesh_terms: D017360:Arabidopsis / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism*; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism*; D018869:Heat-Shock Response / Q000502:physiology*; D013347:Subcellular Fractions / Q000378:metabolism*; D014018:Tissue Distribution
chemical_list: D002352:Carrier Proteins; D018840:HSP70 Heat-Shock Proteins; C572913:hikeshi protein, human
keywords: Arabidopsis; Heat shock protein; Nuclear carrier protein; Thermotolerance; Transgenic plants