Masahiro Mizutani

Publications (2)5.98 Total impact

• Article: Aquaporin NIP2;1 is mainly localized to the ER membrane and shows root-specific accumulation in Arabidopsis thaliana.

  Masahiro Mizutani, Satoshi Watanabe, Tsuyoshi Nakagawa, Masayoshi Maeshima
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  ABSTRACT: We investigated a nodulin 26-like protein NIP2;1, which belongs to the third subgroup of Arabidopsis aquaporins. Histochemical analysis of a promoter-beta-glucuronidase fusion revealed the root-specific expression of NIP2;1. The NIP2;1 protein was detected in young roots, but not in leaves, stems, flowers or siliques. The transient expression of NIP2;1 linked with green fluorescent protein in Arabidopsis cultured cells showed its putative endoplasmic reticulum (ER) localization. NIP2;1 expressed in yeast cells had low water channel activity in the membranes. NIP2;1 may function as a water channel and/or ER channel for other small molecules or ions.
  Plant and Cell Physiology 11/2006; 47(10):1420-6. · 4.70 Impact Factor
• Article: Immunochemical analysis of aquaporin isoforms in Arabidopsis suspension-cultured cells.

  Yoshihiro Kobae, Masahiro Mizutani, Shoji Segami, Masayoshi Maeshima
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  ABSTRACT: Aquaporins mediate the movement of water across biomembranes. Arabidopsis thaliana contains 35 aquaporins that belong to four subfamilies (PIP, TIP, SIP, and NIP). We investigated their expression profiles immunochemically in suspension-cultured Arabidopsis thaliana cells during growth and in response to salt and osmotic stresses. Protein amounts of all aquaporins were much lower in cultured cells than in the plant tissues. This is consistent with the low water permeability of protoplasts from cultured cells. After treatment with NaCl, the protein amounts of PIP2;1, PIP2;2, and PIP2;3 in the cells increased several-fold, and those of TIP1;1 and TIP1;2, 15- and 3-fold respectively. PIP1 did not change under the stress. Cell death began after 19 d in culture, accompanied by marked accumulation of PIPs and TIPs and a gradual decrease in SIPs. Our results suggest the followings: (i) Accumulation of aquaporin isoforms was individually regulated at low levels in single cells. (ii) At least PIP2;2, PIP2;3, TIP1;1, and TIP1;2 are stress-responsive aquaporins in suspension cells. (iii) A sudden increment of several members of PIP2 and TIP1 subfamilies might be related to cell death.
  Bioscience Biotechnology and Biochemistry 05/2006; 70(4):980-7. · 1.28 Impact Factor