A new regulation mechanism for KCNN4, the Ca2+-dependent K+ channel, by molecular interactions with the Ca2+pump PMCA4b.

IF 4 2区 生物学 Q2 BIOCHEMISTRY & MOLECULAR BIOLOGY
Journal of Biological Chemistry Pub Date : 2025-02-01 Epub Date: 2024-12-21 DOI:10.1016/j.jbc.2024.108114
Benoit Allegrini, Morgane Mignotet, Raphaël Rapetti-Mauss, Franck Borgese, Olivier Soriani, Hélène Guizouarn
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引用次数: 0

Abstract

KCNN4, a Ca2+-activated K+ channel, is involved in various physiological and pathological processes. It is essential for epithelial transport, immune system, and other physiological mechanisms, but its activation is also involved in cancer pathophysiology as well as red blood cell (RBC) disorders. The activation of KCNN4 in RBC leads to loss of KCl and water, a mechanism known as the "Gardos effect" described 70 years ago. This Ca2+-induced dehydration is irreversible in human RBC and must be tightly controlled to prevent not only hemolysis but also alterations in RBC rheological properties. In this study, we have investigated the regulation of KCNN4 activity after changes in RBC Ca2+ concentration. Using electrophysiology, immunoprecipitation, and proximity ligation assay in human embryonic kidney 293-transfected cells, K562 cells, or RBCs, we have found that KCNN4 and the Ca2+ pump PMCA4b (plasma membrane calcium-transporting ATPase 4b) interact tightly with each other, such that the C-terminal domain of PMCA4b regulates KCNN4 activity, independently of the Ca2+ extrusion activity of the pump. This regulation was not restricted to KCNN4: the small-conductance Ca2+-activated K+ channel KCNN2 was similarly regulated by the calcium pump. We propose a new mechanism that could control KCNN4 activity by a molecular inhibitory interaction with PMCA4b. It is suggested that this mechanism could attenuate erythrocyte dehydration in response to an increase in intracellular Ca2+.

通过与Ca2+泵PMCA4b的分子相互作用,发现Ca2+依赖性K+通道KCNN4的新调控机制。
KCNN4是Ca2+激活的K+通道,参与多种生理和病理过程。它对上皮运输、免疫系统和其他生理机制至关重要,但其激活也参与癌症病理生理和红细胞疾病(RBC)。红细胞中KCNN4的激活导致KCl和水的损失,这一机制被称为“Gardos效应”,早在70年前就被描述过。这种Ca2+诱导的脱水在人红细胞中是不可逆的,必须严格控制,不仅要防止溶血,还要防止红细胞流变学特性的改变。在这项研究中,我们研究了红细胞Ca2+浓度变化后KCNN4活性的调节。通过对HEK293转染细胞、K562细胞或红细胞的电生理、免疫沉淀和接近结联实验,我们发现KCNN4和Ca2+泵PMCA4b相互作用紧密,因此PMCA4b的c端结构域调节KCNN4的活性,独立于泵的Ca2+挤压活性。这种调节并不局限于KCNN4:小电导Ca2+激活的K+通道KCNN2同样受到钙泵的调节。我们提出了一种新的机制,可以通过与PMCA4b分子抑制相互作用来控制KCNN4的活性。这表明,这种机制可以减轻红细胞脱水响应增加细胞内Ca2+。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
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来源期刊
Journal of Biological Chemistry
Journal of Biological Chemistry Biochemistry, Genetics and Molecular Biology-Biochemistry
自引率
4.20%
发文量
1233
期刊介绍: The Journal of Biological Chemistry welcomes high-quality science that seeks to elucidate the molecular and cellular basis of biological processes. Papers published in JBC can therefore fall under the umbrellas of not only biological chemistry, chemical biology, or biochemistry, but also allied disciplines such as biophysics, systems biology, RNA biology, immunology, microbiology, neurobiology, epigenetics, computational biology, ’omics, and many more. The outcome of our focus on papers that contribute novel and important mechanistic insights, rather than on a particular topic area, is that JBC is truly a melting pot for scientists across disciplines. In addition, JBC welcomes papers that describe methods that will help scientists push their biochemical inquiries forward and resources that will be of use to the research community.
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