FEBS Letters | |
The Ca2+/calmodulin binding domain of the Ca2+‐ATPase linked to the Na+,K+‐ATPase alters transport stoichiometry | |
Yoshimura, Shige H.1  Schwarz, Wolfgang1  Ishii, Toshiaki3  Gu, Quanbao1  Zhao, Jianxing1  Vasilets, Larisa A.1  Takeyasu, Kunio2  | |
[1] Max-Planck Institut für Biophysik, Kennedyallee 70, D-60596 Frankfurt/Main, Germany;Neurobiotechnology Center, Ohio State University, Columbus, OH 43210-1002, USA;Research Institute for Advances in Science and Technology, University of Osaka Prefecture, Osaka 591, Japan | |
关键词: Sodium pump; Alpha-subunit; Beta-subunit; Calmodulin; Ion (Na+) transport; Electrogenicity; | |
DOI : 10.1016/S0014-5793(97)00435-3 | |
学科分类:生物化学/生物物理 | |
来源: John Wiley & Sons Ltd. | |
【 摘 要 】
Using Xenopus oocytes as an expression system, we have investigated ion-transport and ouabain-binding properties of a chimeric ATPase (α1-CBD; Ishii and Takeyasu (1995) EMBO J. 14, 58–67) formed by the α1-subunit of chicken Na+,K+-ATPase (α1) and the calmodulin binding domain (CBD) of the rat plasma membrane Ca2+-ATPase. α1-CBD can be expressed and transported to the oocyte plasma membrane without the β-subunit, and shows ouabain binding. In contrast to ouabain binding, this chimera requires the β-subunit for its cation (Na+ and K+) transport activity. α1-CBD exhibits an altered stoichiometry of Na+-K+ exchange. A detailed analysis of 22Na+ efflux, 86Rb+ uptake, pump current and ouabain binding suggests that the chimeric molecule can operate in an electrically silent 2Na+–2K+ exchange mode and, with much lower probability, in its normal 3Na+–2K+ exchange mode.
【 授权许可】
Unknown
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