scholarly journals Structure and Function of Ion Channels Regulating Sperm Motility—An Overview

2021 ◽  
Vol 22 (6) ◽  
pp. 3259
Author(s):  
Karolina Nowicka-Bauer ◽  
Monika Szymczak-Cendlak
Keyword(s):  
Ion Channels ◽  
Sperm Motility ◽  
Ion Homeostasis ◽  
Internal Factors ◽  
Voltage Gated ◽  
Secondary Messenger ◽  
Cl Channels ◽  
H Channels ◽  
And Function

Sperm motility is linked to the activation of signaling pathways that trigger movement. These pathways are mainly dependent on Ca2+, which acts as a secondary messenger. The maintenance of adequate Ca2+ concentrations is possible thanks to proper concentrations of other ions, such as K+ and Na+, among others, that modulate plasma membrane potential and the intracellular pH. Like in every cell, ion homeostasis in spermatozoa is ensured by a vast spectrum of ion channels supported by the work of ion pumps and transporters. To achieve success in fertilization, sperm ion channels have to be sensitive to various external and internal factors. This sensitivity is provided by specific channel structures. In addition, novel sperm-specific channels or isoforms have been found with compositions that increase the chance of fertilization. Notably, the most significant sperm ion channel is the cation channel of sperm (CatSper), which is a sperm-specific Ca2+ channel required for the hyperactivation of sperm motility. The role of other ion channels in the spermatozoa, such as voltage-gated Ca2+ channels (VGCCs), Ca2+-activated Cl-channels (CaCCs), SLO K+ channels or voltage-gated H+ channels (VGHCs), is to ensure the activation and modulation of CatSper. As the activation of sperm motility differs among metazoa, different ion channels may participate; however, knowledge regarding these channels is still scarce. In the present review, the roles and structures of the most important known ion channels are described in regard to regulation of sperm motility in animals.

scholarly journals Functional Aspects of Seminal Plasma in Bird Reproduction

2020 ◽  
Vol 21 (16) ◽  
pp. 5664
Author(s):  
Julian Santiago-Moreno ◽  
Elisabeth Blesbois
Keyword(s):  
Seminal Plasma ◽  
Ion Homeostasis ◽  
Sperm Concentration ◽  
Cellular Functions ◽  
Functional Aspects ◽  
Reproductive Techniques ◽  
Sperm Survival ◽  
Protein Components ◽  
And Function

This review provides an updated overview of the seminal plasma composition, and the role of metabolic and protein components on the sperm function of avian species. In addition, the implication of seminal plasma on assisted reproductive techniques of birds was discussed. The semen of birds usually has exceptionally high sperm concentration with relatively little seminal plasma, but this contributes to very fast changes in sperm metabolism and function. The biochemical characteristics and physiological roles of the various seminal plasma components in birds (carbohydrates, lipids, amino acids, hormones, and proteins) are poorly understood. Seminal plasma content of proteins has an action on most cellular functions: metabolism, immunity, oxido-reduction regulation, proteolysis, apoptosis, ion homeostasis, and antimicrobial defenses. The variable amount of many proteins is related to a different fertility capacity of poultry sperm. The role of seminal plasma on semen conservation (chilling and freezing) remains largely a matter of speculation, as both inhibitory and stimulating effects have been found. Whereas the presence of seminal plasma did not seem to affect the sperm survival after freezing–thawing, DNA fragmentation is lower in the absence of seminal plasma. The molecular basis of the influence of seminal plasma on sperm cryo-resistance was also discussed in the present review.

scholarly journals Voltage-Gated Potassium Channels as Regulators of Cell Death

2020 ◽  
Vol 8 ◽  
Author(s):  
Magdalena Bachmann ◽  
Weiwei Li ◽  
Michael J. Edwards ◽  
Syed A. Ahmad ◽  
Sameer Patel ◽  
...  
Keyword(s):  
Ion Channels ◽  
Cell Cycle Progression ◽  
Current Knowledge ◽  
Ion Homeostasis ◽  
Cycle Progression ◽  
Voltage Gated ◽  
Proliferation And Apoptosis ◽  
Affect Cell Cycle Progression ◽  
Voltage Gated Channels ◽  
Intracellular Potassium Concentration

Ion channels allow the flux of specific ions across biological membranes, thereby determining ion homeostasis within the cells. Voltage-gated potassium-selective ion channels crucially contribute to the setting of the plasma membrane potential, to volume regulation and to the physiologically relevant modulation of intracellular potassium concentration. In turn, these factors affect cell cycle progression, proliferation and apoptosis. The present review summarizes our current knowledge about the involvement of various voltage-gated channels of the Kv family in the above processes and discusses the possibility of their pharmacological targeting in the context of cancer with special emphasis on Kv1.1, Kv1.3, Kv1.5, Kv2.1, Kv10.1, and Kv11.1.

Novel role for K+-dependent Na+/Ca2+ exchangers in regulation of cytoplasmic free Ca2+ and contractility in arterial smooth muscle

2006 ◽  
Vol 291 (3) ◽  
pp. H1226-H1235 ◽  
Author(s):  
Hui Dong ◽  
Yanfen Jiang ◽  
Chris R. Triggle ◽  
Xiaofang Li ◽  
Jonathan Lytton
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Vascular Tone ◽  
Rt Pcr ◽  
Aortic Smooth Muscle ◽  
Voltage Gated ◽  
Reverse Mode ◽  
And Function ◽  
Contraction And Relaxation

Cytoplasmic free Ca2+ ([Ca2+]cyt) is essential for the contraction and relaxation of blood vessels. The role of plasma membrane Na+/Ca2+ exchange (NCX) activity in the regulation of vascular Ca2+ homeostasis was previously ascribed to the NCX1 protein. However, recent studies suggest that a relatively newly discovered K+-dependent Na+/Ca2+ exchanger, NCKX (gene family SLC24), is also present in vascular smooth muscle. The purpose of the present study was to identify the expression and function of NCKX in arteries. mRNA encoding NCKX3 and NCKX4 was demonstrated by RT-PCR and Northern blot in both rat mesenteric and aortic smooth muscle. NCXK3 and NCKX4 proteins were also demonstrated by immunoblot and immunofluorescence. After voltage-gated Ca2+ channels, store-operated Ca2+ channels, and Na+ pump were pharmacologically blocked, when the extracellular Na+ was replaced with Li+ (0 Na+) to induce reverse mode (Ca2+ entry) activity of Na+/Ca2+ exchangers, a large increase in [Ca2+]cyt signal was observed in primary cultured aortic smooth muscle cells. About one-half of this [Ca2+]cyt signal depended on the extracellular K+. In addition, after the activity of NCX was inhibited by KB-R7943, Na+ replacement-induced Ca2+ entry was absolutely dependent on extracellular K+. In arterial rings denuded of endothelium, a significant fraction of the phenylephrine-induced and nifedipine-resistant aortic or mesenteric contraction could be prevented by removal of extracellular K+. Taken together, these data provide strong evidence for the expression of NCKX proteins in the vascular smooth muscle and their novel role in mediating agonist-stimulated [Ca2+]cyt and thereby vascular tone.

scholarly journals Conserved His-Gly motif of acid-sensing ion channels resides in a reentrant ‘loop’ implicated in gating and ion selectivity

2020 ◽  
Author(s):  
Nate Yoder ◽  
Eric Gouaux
Keyword(s):  
Ion Channels ◽  
Ion Selectivity ◽  
Fear Memory ◽  
Amino Terminus ◽  
Ion Permeation ◽  
Structural Explanation ◽  
Cryo Electron Microscopy ◽  
Acid Sensing Ion Channels ◽  
And Function

ABSTRACTAcid-sensing ion channels (ASICs) are proton-gated members of the epithelial sodium channel/degenerin (ENaC/DEG) superfamily of ion channels and are expressed throughout central and peripheral nervous systems. The homotrimeric splice variant ASIC1a has been implicated in nociception, fear memory, mood disorders and ischemia. Here we extract full-length chicken ASIC1a (cASIC1a) from cell membranes using styrene maleic acid (SMA) copolymer, yielding structures of ASIC1a channels in both high pH resting and low pH desensitized conformations by single-particle cryo-electron microscopy (cryo-EM). The structures of resting and desensitized channels reveal a reentrant loop at the amino terminus of ASIC1a that includes the highly conserved ‘His-Gly’ (HG) motif. The reentrant loop lines the lower ion permeation pathway and buttresses the ‘Gly-Ala-Ser’ (GAS) constriction, thus providing a structural explanation for the role of the His-Gly dipeptide in the structure and function of ASICs.

Channels and electrical signals

2019 ◽  
pp. 37-56
Author(s):  
Gordon L. Fain
Keyword(s):  
Ion Channels ◽  
Hair Cell ◽  
Ion Selectivity ◽  
Ion Homeostasis ◽  
Membrane Conductance ◽  
Sensory Transduction ◽  
Ionotropic Receptor ◽  
Electrical Signals ◽  
Voltage Clamping ◽  
And Function

“Channels and electrical signals” is the third chapter of the book Sensory Transduction and reviews the structure and function of ion channels, the structure of channel pores, and mechanisms of gating. It introduces ionotropic receptor molecules, which are proteins that function as sensory receptors but are also ion channels, whose gating can produce changes in membrane conductance directly. It then uses the hair cell of the inner ear as an example to introduce the concepts of membrane potentials, the Nernst equation, ion homeostasis, the Goldman voltage equation, and driving force. A description of the technique of voltage clamping follows, together with the application of this technique to the hair cell to explain the method of measuring changes in channel gating and the ion selectivity of channel pores.

scholarly journals Voltage gated inter-cation selective ion channels from graphene nanopores

Nanoscale ◽  
2019 ◽  
Vol 11 (20) ◽  
pp. 9856-9861 ◽  
Author(s):  
Lauren Cantley ◽  
Jacob L. Swett ◽  
David Lloyd ◽  
David A. Cullen ◽  
Ke Zhou ◽  
...  
Keyword(s):  
Ion Channels ◽  
Ionic Transport ◽  
Voltage Gated ◽  
Nanoporous Graphene ◽  
Graphene Membranes

The role of nanobubbles in selectively controlled ionic transport across fabricated nanoporous graphene membranes is elucidated.

The role of metal ions in the virulence and viability of bacterial pathogens

2019 ◽  
Vol 47 (1) ◽  
pp. 77-87 ◽  
Author(s):  
Stephanie L. Begg
Keyword(s):  
Metal Ions ◽  
Metal Ion ◽  
Molecular Mechanisms ◽  
Bacterial Pathogens ◽  
Ion Homeostasis ◽  
Transition Metal Ions ◽  
Metal Ion Homeostasis ◽  
And Function ◽  
Iron Manganese

AbstractMetal ions fulfil a plethora of essential roles within bacterial pathogens. In addition to acting as necessary cofactors for cellular proteins, making them indispensable for both protein structure and function, they also fulfil roles in signalling and regulation of virulence. Consequently, the maintenance of cellular metal ion homeostasis is crucial for bacterial viability and pathogenicity. It is therefore unsurprising that components of the immune response target and exploit both the essentiality of metal ions and their potential toxicity toward invading bacteria. This review provides a brief overview of the transition metal ions iron, manganese, copper and zinc during infection. These essential metal ions are discussed in the context of host modulation of bioavailability, bacterial acquisition and efflux, metal-regulated virulence factor expression and the molecular mechanisms that contribute to loss of viability and/or virulence during host-imposed metal stress.

scholarly journals Activation of KCNQ4 as a Therapeutic Strategy to Treat Hearing Loss

2021 ◽  
Vol 22 (5) ◽  
pp. 2510
Author(s):  
John Hoon Rim ◽  
Jae Young Choi ◽  
Jinsei Jung ◽  
Heon Yung Gee
Keyword(s):  
Hearing Loss ◽  
Late Onset ◽  
Ion Homeostasis ◽  
Physiological Role ◽  
Voltage Gated ◽  
Age Related ◽  
Gated Channel ◽  
Pros And Cons ◽  
Age Related Hearing Loss

Potassium voltage-gated channel subfamily q member 4 (KCNQ4) is a voltage-gated potassium channel that plays essential roles in maintaining ion homeostasis and regulating hair cell membrane potential. Reduction of the activity of the KCNQ4 channel owing to genetic mutations is responsible for nonsyndromic hearing loss, a typically late-onset, initially high-frequency loss progressing over time. In addition, variants of KCNQ4 have also been associated with noise-induced hearing loss and age-related hearing loss. Therefore, the discovery of small compounds activating or potentiating KCNQ4 is an important strategy for the curative treatment of hearing loss. In this review, we updated the current concept of the physiological role of KCNQ4 in the inner ear and the pathologic mechanism underlying the role of KCNQ4 variants with regard to hearing loss. Finally, we focused on currently developed KCNQ4 activators and their pros and cons, paving the way for the future development of specific KCNQ4 activators as a remedy for hearing loss.

scholarly journals Pathophysiological Role of K2P Channels in Human Diseases

2021 ◽  
Vol 55 (S3) ◽  
pp. 65-86
Keyword(s):  
Molecular Mechanisms ◽  
Current Knowledge ◽  
Expression Patterns ◽  
Ion Homeostasis ◽  
Human Diseases ◽  
Cellular Functions ◽  
Aberrant Expression ◽  
K2p Channels ◽  
And Function

The family of two-pore domain potassium (K2P) channels is critically involved in central cellular functions such as ion homeostasis, cell development, and excitability. K2P channels are widely expressed in different human cell types and organs. It is therefore not surprising that aberrant expression and function of K2P channels are related to a spectrum of human diseases, including cancer, autoimmune, CNS, cardiovascular, and urinary tract disorders. Despite homologies in structure, expression, and stimulus, the functional diversity of K2P channels leads to heterogeneous influences on human diseases. The role of individual K2P channels in different disorders depends on expression patterns and modulation in cellular functions. However, an imbalance of potassium homeostasis and action potentials contributes to most disease pathologies. In this review, we provide an overview of current knowledge on the role of K2P channels in human diseases. We look at altered channel expression and function, the potential underlying molecular mechanisms, and prospective research directions in the field of K2P channels.

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