title: Water channel activities of Mimosa pudica plasma membrane intrinsic proteins are regulated by direct interaction and phosphorylation.
abstract: cDNAs encoding aquaporins PIP1;1, PIP2;1, and TIP1;1 were isolated from Mimosa pudica (Mp) cDNA library. MpPIP1;1 exhibited no water channel activity; however, it facilitated the water channel activity of MpPIP2;1 in a phosphorylation-dependent manner. Mutagenesis analysis revealed that Ser-131 of MpPIP1;1 was phosphorylated by PKA and that cooperative regulation of the water channel activity of MpPIP2;1 was regulated by phosphorylation of Ser-131 of MpPIP1;1. Immunoprecipitation analysis revealed that MpPIP1;1 binds directly to MpPIP2;1 in a phosphorylation-independent manner, suggesting that phosphorylation of Ser-131 of MpPIP1;1 is involved in regulation of the structure of the channel complex with MpMIP2;1 and thereby affects water channel activity.
authors.affiliation: Department of Chemistry, Faculty of Science and Technology, Sophia University, 7-1 Kioi, Chiyoda-ku, Tokyo 102-8554, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Temmei
authors.forename: Shinichi
authors.initials: S
authors.lastname: Uchida
authors.forename: Daisuke
authors.initials: D
authors.lastname: Hoshino
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Kanzawa
authors.forename: Michio
authors.initials: M
authors.lastname: Kuwahara
authors.forename: Sei
authors.initials: S
authors.lastname: Sasaki
authors.forename: Takahide
authors.initials: T
authors.lastname: Tsuchiya
mesh_terms: D000818:Animals; D020346:Aquaporins / Q000235:genetics / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D015723:Gene Library; D047468:Immunoprecipitation; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D031298:Mimosa / Q000235:genetics / Q000378:metabolism*; D016296:Mutagenesis; D009865:Oocytes / Q000378:metabolism; D010766:Phosphorylation; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D014981:Xenopus
chemical_list: D020346:Aquaporins; D008565:Membrane Proteins; D010940:Plant Proteins; D017868:Cyclic AMP-Dependent Protein Kinases