Differential modulation of SK channel subtypes by phosphorylation

Nam, Young‐Woo; Kong, Dezhi; Wang, Dong; Orfali, Razan; Sherpa, Rinzhin T.; Totonchy, Jennifer; Nauli, Surya M.; Zhang, Miao

doi:10.1016/j.ceca.2020.102346

Cited by 11 publications

(11 citation statements)

References 63 publications

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“…Recently, we identified K Ca 2.3 channels as the predominant subtype expressed in a mouse ET cell line, whereas the expression of K Ca 2.1, K Ca 2.2, and K Ca 3.1 channel subtypes was not detected by immunoblots. 36 Thus, we examined whether negative modulation by AP14145 of K Ca 2.3 channels affected the cilia length of the ET cells. AP14145 inhibited K Ca 2.3 channels with an IC 50 value of 0.97 ± 0.39 μM ( n = 5, Figure S5 ).…”

Section: Resultsmentioning

confidence: 99%

“…The ET cells do not express K Ca 2.1, K Ca 2.2, and K Ca 3.1 channels. 36 Therefore, the effect of apamin on the ET cells is mediated by the K Ca 2.3 channel blockade.…”

Section: Resultsmentioning

confidence: 99%

“…A bee venom toxin, apamin (50 nM), that selectively blocks K Ca 2 channels, completely abolished the elongating effect of compound 4 on cilia (Figure S7B,C). The ET cells do not express K Ca 2.1, K Ca 2.2, and K Ca 3.1 channels . Therefore, the effect of apamin on the ET cells is mediated by the K Ca 2.3 channel blockade.…”

Section: Resultsmentioning

confidence: 99%

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Subtype-Selective Positive Modulation of K_Ca2.3 Channels Increases Cilia Length

et al. 2022

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Small-conductance Ca 2+ -activated potassium (K Ca 2.x) channels are gated exclusively by intracellular Ca 2+ . The activation of K Ca 2.3 channels induces hyperpolarization, which augments Ca 2+ signaling in endothelial cells. Cilia are specialized Ca 2+ signaling compartments. Here, we identified compound 4 that potentiates human K Ca 2.3 channels selectively. The subtype selectivity of compound 4 for human K Ca 2.3 over rat K Ca 2.2a channels relies on an isoleucine residue in the HA/HB helices. Positive modulation of K Ca 2.3 channels by compound 4 increased flow-induced Ca 2+ signaling and cilia length, while negative modulation by AP14145 reduced flow-induced Ca 2+ signaling and cilia length. These findings were corroborated by the increased cilia length due to the expression of Ca 2+ -hypersensitive K Ca 2.3_G351D mutant channels and the reduced cilia length resulting from the expression of Ca 2+ -hyposensitive K Ca 2.3_I438N channels. Collectively, we were able to associate functions of K Ca 2.3 channels and cilia, two crucial components in the flow-induced Ca 2+ signaling of endothelial cells, with potential implications in vasodilation and ciliopathic hypertension.

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Section: Resultsmentioning

confidence: 99%

“…The ET cells do not express K Ca 2.1, K Ca 2.2, and K Ca 3.1 channels. 36 Therefore, the effect of apamin on the ET cells is mediated by the K Ca 2.3 channel blockade.…”

Section: Resultsmentioning

confidence: 99%

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Subtype-Selective Positive Modulation of K_Ca2.3 Channels Increases Cilia Length

et al. 2022

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“…To clarify the similarities and differences between hiPSC-ECs and native ECs, to determine the usefulness and importance of hiPSC-ECs in endothelial researches, we employed qPCR to study ion channels in our hiPSC-ECs and compared them with HCMECs. The expression of SK1 channels in isolated and cultured ECs were rarely detected, while the mRNA of SK2 channels were easily detectable [ 35 , 36 , 37 , 38 ]. Our study demonstrated that the expression of KCNN4 (SK4) gene, KCNMA1 (BK) gene, TRPV2 gene, SLC8A1 gene and KCNN2 (SK2) gene in hiPSC-ECs exhibited a much higher expression than HCMECs.…”

Section: Discussionmentioning

confidence: 99%

“…In this study, no significant difference in RP between hiPSC-ECs and HCMECs was observed. Currently, only several channel currents in ECs have been investigated, mainly focusing on I SK1–3 , I SK4 , I BK , I K1, and, I KATP [ 27 , 35 , 38 , 41 , 42 , 43 , 44 , 45 , 46 , 47 ], which were not studied in hiPSC-ECs. Thus, in our study, we mainly compared the current density of I SK1–3 , I SK4 , I BK , I K1, and I KATP in hiPSC-ECs with that of HCMECs.…”

Section: Discussionmentioning

confidence: 99%

Functional Characterization of Human Induced Pluripotent Stem Cell-Derived Endothelial Cells

Fan

Cyganek

Nitschke

et al. 2022

IJMS

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Endothelial cells derived from human induced pluripotent stem cells (hiPSC-ECs) provide a new opportunity for mechanistic research on vascular regeneration and drug screening. However, functions of hiPSC-ECs still need to be characterized. The objective of this study was to investigate electrophysiological and functional properties of hiPSC-ECs compared with primary human cardiac microvascular endothelial cells (HCMECs), mainly focusing on ion channels and membrane receptor signaling, as well as specific cell functions. HiPSC-ECs were derived from hiPS cells that were generated from human skin fibroblasts of three independent healthy donors. Phenotypic and functional comparison to HCMECs was performed by flow cytometry, immunofluorescence staining, quantitative reverse-transcription polymerase chain reaction (qPCR), enzyme-linked immunosorbent assay (ELISA), tube formation, LDL uptake, exosome release assays and, importantly, patch clamp techniques. HiPSC-ECs were successfully generated from hiPS cells and were identified by endothelial markers. The mRNA levels of KCNN2, KCNN4, KCNMA1, TRPV2, and SLC8A1 in hiPSC-ECs were significantly higher than HCMECs. AT1 receptor mRNA level in hiPSC-ECs was higher than in HCMECs. AT2 receptor mRNA level was the highest among all receptors. Adrenoceptor ADRA2 expression in hiPSC-ECs was lower than in HCMECs, while ADRA1, ADRB1, ADRB2, and G-protein GNA11 and Gai expression were similar in both cell types. The expression level of muscarinic and dopamine receptors CHRM3, DRD2, DRD3, and DRD4 in hiPSC-ECs were significantly lower than in HCMECs. The functional characteristics of endothelial cells, such as tube formation and LDL uptake assay, were not statistically different between hiPSC-ECs and HCMECs. Phenylephrine similarly increased the release of the vasoconstrictor endothelin-1 (ET-1) in hiPSC-ECs and HCMECs. Acetylcholine also similarly increased nitric oxide generation in hiPSC-ECs and HCMECs. The resting potentials (RPs), ISK1–3, ISK4 and IK1 were similar in hiPSC-ECs and HCMECs. IBK was larger and IKATP was smaller in hiPSC-ECs. In addition, we also noted a higher expression level of exosomes marker CD81 in hiPSC-ECs and a higher expression of CD9 and CD63 in HCMECs. However, the numbers of exosomes extracted from both types of cells did not differ significantly. The study demonstrates that hiPSC-ECs are similar to native endothelial cells in ion channel function and membrane receptor-coupled signaling and physiological cell functions, although some differences exist. This information may be helpful for research using hiPSC-ECs.

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K_Ca2.2 (KCNN2): A physiologically and therapeutically important potassium channel

Rahman,

Orfali,

Dave

et al. 2023

J of Neuroscience Research

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One group of the K+ ion channels, the small‐conductance Ca2+‐activated potassium channels (KCa2.x, also known as SK channels family), is widely expressed in neurons as well as the heart, endothelial cells, etc. They are named small‐conductance Ca2+‐activated potassium channels (SK channels) due to their comparatively low single‐channel conductance of about ~10 pS. These channels are insensitive to changes in membrane potential and are activated solely by rises in the intracellular Ca2+. According to the phylogenic research done on the KCa2.x channels family, there are three channels' subtypes: KCa2.1, KCa2.2, and KCa2.3, which are encoded by KCNN1, KCNN2, and KCNN3 genes, respectively. The KCa2.x channels regulate neuronal excitability and responsiveness to synaptic input patterns. KCa2.x channels inhibit excitatory postsynaptic potentials (EPSPs) in neuronal dendrites and contribute to the medium afterhyperpolarization (mAHP) that follows the action potential bursts. Multiple brain regions, including the hippocampus, express the KCa2.2 channel encoded by the KCNN2 gene on chromosome 5. Of particular interest, rat cerebellar Purkinje cells express KCa2.2 channels, which are crucial for various cellular processes during development and maturation. Patients with a loss‐of‐function of KCNN2 mutations typically exhibit extrapyramidal symptoms, cerebellar ataxia, motor and language developmental delays, and intellectual disabilities. Studies have revealed that autosomal dominant neurodevelopmental movement disorders resembling rodent symptoms are caused by heterozygous loss‐of‐function mutations, which are most likely to induce KCNN2 haploinsufficiency. The KCa2.2 channel is a promising drug target for spinocerebellar ataxias (SCAs). SCAs exhibit the dysregulation of firing in cerebellar Purkinje cells which is one of the first signs of pathology. Thus, selective KCa2.2 modulators are promising potential therapeutics for SCAs.

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Differential modulation of SK channel subtypes by phosphorylation

Cited by 11 publications

References 63 publications

Subtype-Selective Positive Modulation of K_Ca2.3 Channels Increases Cilia Length

Subtype-Selective Positive Modulation of K_Ca2.3 Channels Increases Cilia Length

Functional Characterization of Human Induced Pluripotent Stem Cell-Derived Endothelial Cells

K_Ca2.2 (KCNN2): A physiologically and therapeutically important potassium channel

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Differential modulation of SK channel subtypes by phosphorylation

Cited by 11 publications

References 63 publications

Subtype-Selective Positive Modulation of KCa2.3 Channels Increases Cilia Length

Subtype-Selective Positive Modulation of KCa2.3 Channels Increases Cilia Length

Functional Characterization of Human Induced Pluripotent Stem Cell-Derived Endothelial Cells

KCa2.2 (KCNN2): A physiologically and therapeutically important potassium channel

Contact Info

Product

Resources

About

Subtype-Selective Positive Modulation of K_Ca2.3 Channels Increases Cilia Length

Subtype-Selective Positive Modulation of K_Ca2.3 Channels Increases Cilia Length

K_Ca2.2 (KCNN2): A physiologically and therapeutically important potassium channel