Effects of syntaxins 2, 3, and 4 on rat and human epithelial sodium channel (ENaC) in Xenopus laevis oocytes

Rauh, R. D.; Frost, Fabian; Korbmacher, Christoph

doi:10.1007/s00424-020-02365-6

Cited by 3 publications

(1 citation statement)

References 68 publications

(113 reference statements)

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“…Oocytes were collected from Xenopus laevis with approval of the animal welfare officer for the University of Erlangen-Nürnberg as described [ 13 , 17 , 23 , 33 , 37 ]. Defolliculated stage V–VI oocytes were injected with cRNA encoding human α-, β-, and γ-ENaC (0.2 ng of cRNA/subunit of human wild-type α-, β- and γ- or mutant γRKRK178AAAA ENaC).…”

Section: Methodsmentioning

confidence: 99%

Proteolytic activation of the epithelial sodium channel (ENaC) by factor VII activating protease (FSAP) and its relevance for sodium retention in nephrotic mice

Artunc

Bohnert

Schneider

et al. 2021

Pflugers Arch - Eur J Physiol

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Proteolytic activation of the epithelial sodium channel (ENaC) by aberrantly filtered serine proteases is thought to contribute to renal sodium retention in nephrotic syndrome. However, the identity of the responsible proteases remains elusive. This study evaluated factor VII activating protease (FSAP) as a candidate in this context. We analyzed FSAP in the urine of patients with nephrotic syndrome and nephrotic mice and investigated its ability to activate human ENaC expressed in Xenopus laevis oocytes. Moreover, we studied sodium retention in FSAP-deficient mice (Habp2−/−) with experimental nephrotic syndrome induced by doxorubicin. In urine samples from nephrotic humans, high concentrations of FSAP were detected both as zymogen and in its active state. Recombinant serine protease domain of FSAP stimulated ENaC-mediated whole-cell currents in a time- and concentration-dependent manner. Mutating the putative prostasin cleavage site in γ-ENaC (γRKRK178AAAA) prevented channel stimulation by the serine protease domain of FSAP. In a mouse model for nephrotic syndrome, active FSAP was present in nephrotic urine of Habp2+/+ but not of Habp2−/− mice. However, Habp2−/− mice were not protected from sodium retention compared to nephrotic Habp2+/+ mice. Western blot analysis revealed that in nephrotic Habp2−/− mice, proteolytic cleavage of α- and γ-ENaC was similar to that in nephrotic Habp2+/+ animals. In conclusion, active FSAP is excreted in the urine of nephrotic patients and mice and activates ENaC in vitro involving the putative prostasin cleavage site of γ-ENaC. However, endogenous FSAP is not essential for sodium retention in nephrotic mice.

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Section: Methodsmentioning

confidence: 99%

Proteolytic activation of the epithelial sodium channel (ENaC) by factor VII activating protease (FSAP) and its relevance for sodium retention in nephrotic mice

Artunc

Bohnert

Schneider

et al. 2021

Pflugers Arch - Eur J Physiol

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Identification of a Novel RUNX1::STX2 Fusion in Mixed‐Phenotype Acute Leukemia (MPAL) With BCR::ABL1

Long,

Xu,

et al. 2024

Molecular Carcinogenesis

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Mixed phenotype acute leukemia (MPAL) is a rare type of acute leukemia (AL), MPAL with BCR::ABL1 fusion is the main subtype of MPAL, mainly affecting adult males. It is an acute leukemia with unique clinical and biological characteristics that involve both the myeloid and lymphatic systems. Gene fusion plays a crucial role in the pathogenesis, diagnosis, prognosis assessment, and treatment of leukemia. We present the first discovery of a novel fusion of RUNX1::STX2 in this subtype, which is co‐expressed with BCR::ABL1 fusion. RUNX1 is a crucial transcription factor for hematopoietic differentiation, frequently found to be abnormal in AML, while STX2 may play a role in cancer progression. The RUNX1::STX2 fusion protein may act as the primary negative regulator of wild‐type RUNX1, influencing normal cell differentiation and proliferation, consequently elevating the risk of leukemia. The gene fusion status of this patient is unique and complex, requiring further exploration to understand its functional significance in leukemia progression and treatment response.

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Actin dynamics as critical ion channel regulator: ENaC and Piezo in focus

Morachevskaya

Sudarikova

2021

American Journal of Physiology-Cell Physiology

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Ion channels in plasma membrane play a principal role in different physiological processes, including cell volume regulation, signal transduction and modulation of membrane potential in living cells. Actin-based cytoskeleton, which exists in a dynamic balance between monomeric and polymeric forms (globular and fibrillar actin), can be directly or indirectly involved in various cellular responses including modulation of ion channel activity. In this mini-review, we present an overview of the role of submembranous actin dynamics in the regulation of ion channels in excitable and non-excitable cells. Special attention is focused on the important data about the involvement of actin assembly/disassembly and some actin-binding proteins in the control of the Epithelial Na+ Channel (ENaC) and mechanosensitive Piezo channels whose integral activity has potential impact on membrane transport and multiple coupled cellular reactions. Growing evidence suggests that actin elements of the cytoskeleton can represent a "converging point" of various signaling pathways modulating the activity of ion transport proteins in cell membranes.

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Effects of syntaxins 2, 3, and 4 on rat and human epithelial sodium channel (ENaC) in Xenopus laevis oocytes

Cited by 3 publications

References 68 publications

Proteolytic activation of the epithelial sodium channel (ENaC) by factor VII activating protease (FSAP) and its relevance for sodium retention in nephrotic mice

Proteolytic activation of the epithelial sodium channel (ENaC) by factor VII activating protease (FSAP) and its relevance for sodium retention in nephrotic mice

Identification of a Novel RUNX1::STX2 Fusion in Mixed‐Phenotype Acute Leukemia (MPAL) With BCR::ABL1

Actin dynamics as critical ion channel regulator: ENaC and Piezo in focus

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