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Your search keyword '"Kameyama, Masaki"' showing total 409 results
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409 results on '"Kameyama, Masaki"'

113. Bio-Assessment of RISK in Long-Term Manned Space Exploration-Cell Death Factors in Space Radiation and/or Microgravity: A Review-

Author

J. Majima, Hideyuki, primary, P. Indo, Hiroko, additional, Tomita, Kazuo, additional, Iwashita, Yoichiro, additional, Suzuki, Hiromi, additional, Masuda, Daisuke, additional, Shimazu, Toru, additional, Tanigaki, Fumiaki, additional, Umemura, Sayaka, additional, Yano, Sachiko, additional, Fukui, Kei, additional, Higashibata, Akira, additional, Q Yamazaki, Takashi, additional, Kameyama, Masaki, additional, Suenaga, Shigeaki, additional, Sato, Tsuyoshi, additional, Yen, Hsiu-Chuan, additional, Gusev, Oleg, additional, Okuda, Takashi, additional, Matsui, Hirofumi, additional, Ozawa, Toshihiko, additional, and Ishioka, Noriaki, additional

Published
2009
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124. PKA and phosphatases attached to the CaV1.2 channel regulate channel activity in cell-free patches.

Author

Jianjun Xu, Lifeng Yu, Etsuko Minobe, Liting Lu, Ming Lei, and Kameyama, Masaki

Subjects
MUSCLE cells, CALMODULIN, CALCIUM channels, ADENOSINE triphosphate, PROTEIN kinase inhibitors
Abstract

00157.2015.--Calmodulin (CaM) ATP can reprime voltage-gated L-type Ca2+ channels (CaV1.2) in inside-out patches for activation, but this effect decreases time dependently. This suggests that the CaV1.2 channel activity is regulated by additional cytoplasmic factors. To test this hypothesis, we examined the role of cAMP-dependent protein kinase A (PKA) and protein phosphatases in the regulation of CaV1.2 channel activity in the inside-out mode in guinea pig ventricular myocytes. CaV1.2 channel activity quickly disappeared after the patch was excised from the cell and recovered to only 9% of that in the cell-attached mode on application of CaM + ATP at 10 min after the inside out. However, immediate exposure of the excised patch to the catalytic subunit of PKA + ATP or the nonspecific phosphatase inhibitor okadaic acid significantly increased the CaV1.2 channel activity recovery by CaM + ATP (114 and 96%, respectively) at 10 min. Interestingly, incubation of the excised patches with cAMP + ATP also increased CaM/ATP-induced CaV1.2 channel activity recovery (108%), and this effect was blocked by the nonspecific protein kinase inhibitor K252a. The channel activity in the inside-out mode was not maintained by either catalytic subunit of PKA or cAMP + ATP in the absence of CaM, but was stably maintained in the presence of CaM for more than 40 min. These results suggest that PKA and phosphatase(s) attached on or near the CaV1.2 channel regulate the basal channel activity, presumably through modulation of the dynamic CaM interaction with the channel. [ABSTRACT FROM AUTHOR]

Published
2016
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142. Isaacs' syndrome as a potassium channelopathy of the nerve

Author

Arimura, Kimiyoshi, primary, Sonoda, Yoshito, additional, Watanabe, Osamu, additional, Nagado, Tatsui, additional, Kurono, Asutsugu, additional, Tomimitsu, Hisanori, additional, Otsuka, Reika, additional, Kameyama, Masaki, additional, and Osame, Mitsuhiro, additional

Published
2002
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150. Adenosine triphosphate regulates the activity of guinea pig Cav1.2 channel by direct binding to the channel in a dose-dependent manner.

Author

Rui Feng, Jianjun Xu, Minobe, Etsuko, Kameyama, Asako, Lei Yang, Lifeng Yu, Liying Hao, and Kameyama, Masaki

Subjects
ADENOSINE triphosphate, GUINEA pigs as laboratory animals, COLLAGENASES, PHOSPHORYLATION, CALMODULIN, ATP-binding cassette transporters
Abstract

The present study is to investigate the mechanism by which ATP regulates Cav1.2 channel activity. Ventricular tissue was obtained from adult guinea pig hearts using collagenase. Ca2+ channel activity was monitored using the patch-clamp technique. Proteins were purified using wheat germ agglutinin-Sepharose, and the concentration was determined using the Coomassie brilliant blue technique. ATP binding to the Cav1.2 channel was examined using the photoaffinity method. EDA-ATPbiotin maintains Ca2+ channel activity in inside-out membrane patches. ATP directly bound to the Cav1.2 channel in a dosedependent manner, and at least two molecules of ATP bound to one molecule of the Cav1.2 channel. Low levels of calmodulin (CaM) increased ATP binding to the Cav1.2 channel, but higher levels of CaM decreased ATP binding to the Cav1.2 channel. In addition, Ca2+ was another regulator for ATP binding to the Cav1.2 channel. Furthermore, ATP bound to GST-fusion peptides of NH2-terminal region (amino acids 6-140) and proximal COOH-terminal region (amino acids 1,509 -1,789) of the main subunit (ɑ1C) of the Cav1.2 channel. Our data suggest that ATP might regulate Cav1.2 channel activity by directly binding to the Cav1.2 channel in a dose-dependent manner. In addition, the ATP-binding effect to the Cav1.2 channel was both CaM- and Ca2+ dependent. [ABSTRACT FROM AUTHOR]

Published
2014
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