2-APB-potentiated channels amplify CatSper-induced Ca2+ signals in human sperm
| Autor: | Sarah Costello, Jennifer Morris, Emma L. Punt, Stephen J. Publicover, Steven A. Mansell, Joao Correia, Jackson Kirkman-Brown, Christopher L.R. Barratt, Linda Lefièvre, Stuart M. Wilson, Katherine Nash |
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| Jazyk: | angličtina |
| Rok vydání: | 2012 |
| Předmět: |
Male
ORAI1 Protein Biochemistry 0302 clinical medicine Sperm motility Calcium signaling GFP green fluorescent protein 0303 health sciences 030219 obstetrics & reproductive medicine Hyperactivation Voltage-dependent calcium channel store-operated channel IP3R inositol trisphosphate receptor STIM1 TRPV3 transient receptor potential vanilloid 3 Spermatozoa Cell biology Neoplasm Proteins CCD charge-coupled-device Sperm Motility OGB Oregon Green BAPTA SOC store-operated channel Sperm Midpiece Research Article Boron Compounds medicine.medical_specialty ORAI2 Protein BCECF 2′ 7′-bis-(2-carboxyethyl)-5(6)-carboxyfluorescein Biology hyperactivation progesterone In Vitro Techniques sperm DVF divalent-free Loperamide 03 medical and health sciences HEK human embryonic kidney 2-APB 2-aminoethoxydiphenyl borate CatSper Internal medicine medicine Humans Calcium Signaling Stromal Interaction Molecule 1 Stromal Interaction Molecule 2 Molecular Biology PHN posterior head and neck 030304 developmental biology calcium sEBSS supplemented Earle’s balanced salt solution Membrane Proteins Cell Biology Sperm CCE capacitative Ca2+ entry Calcium Channel Agonists Endocrinology SERCA sarcoplasmic/endoplasmic reticulum Ca2+-ATPase STIM stromal interaction molecule sense organs TRPC transient receptor potential canonical Calcium Channels Cell Adhesion Molecules |
| Zdroj: | Biochemical Journal |
| ISSN: | 1470-8728 0264-6021 |
| Popis: | Ca2+i signalling is pivotal to sperm function. Progesterone, the best-characterized agonist of human sperm Ca2+i signalling, stimulates a biphasic [Ca2+]i rise, comprising a transient and subsequent sustained phase. In accordance with recent reports that progesterone directly activates CatSper, the [Ca2+]i transient was detectable in the anterior flagellum (where CatSper is expressed) 1–2 s before responses in the head and neck. Pre-treatment with 5 μM 2-APB (2-aminoethoxydiphenyl borate), which enhances activity of store-operated channel proteins (Orai) by facilitating interaction with their activator [STIM (stromal interaction molecule)] ‘amplified’ progesterone-induced [Ca2+]i transients at the sperm neck/midpiece without modifying kinetics. The flagellar [Ca2+]i response was unchanged. 2-APB (5 μM) also enhanced the sustained response in the midpiece, possibly reflecting mitochondrial Ca2+ accumulation downstream of the potentiated [Ca2+]i transient. Pre-treatment with 50–100 μM 2-APB failed to potentiate the transient and suppressed sustained [Ca2+]i elevation. When applied during the [Ca2+]i plateau, 50–100 μM 2-APB caused a transient fall in [Ca2+]i, which then recovered despite the continued presence of 2-APB. Loperamide (a chemically different store-operated channel agonist) enhanced the progesterone-induced [Ca2+]i signal and potentiated progesterone-induced hyperactivated motility. Neither 2-APB nor loperamide raised pHi (which would activate CatSper) and both compounds inhibited CatSper currents. STIM and Orai were detected and localized primarily to the neck/midpiece and acrosome where Ca2+ stores are present and the effects of 2-APB are focussed, but store-operated currents could not be detected in human sperm. We propose that 2-APB-sensitive channels amplify [Ca2+]i elevation induced by progesterone (and other CatSper agonists), amplifying, propagating and providing spatio-temporal complexity in [Ca2+]i signals of human sperm. |
| Databáze: | OpenAIRE |
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