CatSper1 required for evoked Ca2+ entry and control of flagellar function in sperm.
Ontology highlight
ABSTRACT:
SUBMITTER: Carlson AE
PROVIDER: S-EPMC299831 | biostudies-literature | 2003 Dec
REPOSITORIES: biostudies-literature
Publications
CatSper1 required for evoked Ca2+ entry and control of flagellar function in sperm.
Carlson Anne E AE Westenbroek Ruth E RE Quill Timothy T Ren Dejian D Clapham David E DE Hille Bertil B Garbers David L DL Babcock Donner F DF
Proceedings of the National Academy of Sciences of the United States of America 20031201 25
CatSper family proteins are putative ion channels expressed exclusively in membranes of the sperm flagellum and required for male fertility. Here, we show that mouse CatSper1 is essential for depolarization-evoked Ca2+ entry and for hyperactivated movement, a key flagellar function. CatSper1 is not needed for other developmental landmarks, including regional distributions of CaV1.2, CaV2.2, and CaV2.3 ion channel proteins, the cAMP-mediated activation of motility by HCO3-, and the protein phosph ...[more]
Similar Datasets
Project description:Cyclic nucleotide-gated (CNG) channels are key elements of cGMP- and cAMP-signaling pathways in vertebrate photoreceptor cells and in olfactory sensory neurons, respectively. These channels form heterooligomeric complexes composed of at least two distinct subunits (alpha and beta). The alpha subunit of cone photoreceptors is also present in mammalian sperm. Here we identify one short and several long less abundant transcripts of beta subunits in testis. The alpha and beta subunits are expressed in a characteristic temporal and spatial pattern in sperm and precursor cells. In mature sperm, the alpha subunit is observed along the entire flagellum, whereas the short beta subunit is restricted to the principal piece of the flagellum. These findings suggest that different forms of CNG channels coexist in the flagellum. Confocal microscopy in conjunction with the Ca2+ indicator Fluo-3 shows that the CNG channels serve as a Ca2+ entry pathway that responds more sensitively to cGMP than to cAMP. Assuming that CNG channel subtypes differ in their Ca2+ permeability, dissimilar localization of alpha and beta subunits may give rise to a pattern of Ca2+ microdomains along the flagellum, thereby providing the structural basis for control of flagellar bending waves.
| S-EPMC2133051 | biostudies-literature
Project description:In order to fertilize, mammalian sperm must hyperactivate. Hyperactivation is triggered by increased flagellar Ca(2+), which switches flagellar beating from a symmetrical to an asymmetrical pattern by increasing bending to one side. Thimerosal, which releases Ca(2+) from internal stores, induced hyperactivation in mouse sperm within seconds, even when extracellular Ca(2+) was buffered with BAPTA to approximately 30 nM. In sperm from CatSper1 or CatSper2 null mice, which lack functional flagellar alkaline-activated calcium currents, 50 microM thimerosal raised the flagellar bend amplitudes from abnormally low levels to normal pre-hyperactivated levels and, in 20-40% of sperm, induced hyperactivation. Addition of 1 mM Ni(2+) diminished the response. This suggests that intracellular Ca(2+) is abnormally low in the null sperm flagella. When intracellular Ca(2+) was reduced by BAPTA-AM in wild-type sperm, they exhibited flagellar beat patterns more closely resembling those of null sperm. Altogether, these results indicate that extracellular Ca(2+) is required to supplement store-released Ca(2+) to produce maximal and sustained hyperactivation and that CatSper1 and CatSper2 are key elements of the major Ca(2+) entry pathways that support not only hyperactivated motility but possibly also normal pre-hyperactivated motility.
| S-EPMC1885980 | biostudies-literature
Project description:Store-operated Ca(2+) entry (SOCE) through Ca(2+) release-activated Ca(2+) (CRAC) channels is essential for immunity to infection. CRAC channels are formed by ORAI1 proteins in the plasma membrane and activated by stromal interaction molecule (STIM)1 and STIM2 in the endoplasmic reticulum. Mutations in ORAI1 and STIM1 genes that abolish SOCE cause severe immunodeficiency with recurrent infections due to impaired T cell function. SOCE has also been observed in cells of the innate immune system such as macrophages and dendritic cells (DCs) and may provide Ca(2+) signals required for their function. The specific role of SOCE in macrophage and DC function, as well as its contribution to innate immunity, however, is not well defined. We found that nonselective inhibition of Ca(2+) signaling strongly impairs many effector functions of bone marrow-derived macrophages and bone marrow-derived DCs, including phagocytosis, inflammasome activation, and priming of T cells. Surprisingly, however, macrophages and DCs from mice with conditional deletion of Stim1 and Stim2 genes, and therefore complete inhibition of SOCE, showed no major functional defects. Their differentiation, FcR-dependent and -independent phagocytosis, phagolysosome fusion, cytokine production, NLRP3 inflammasome activation, and their ability to present Ags to activate T cells were preserved. Our findings demonstrate that STIM1, STIM2, and SOCE are dispensable for many critical effector functions of macrophages and DCs, which has important implications for CRAC channel inhibition as a therapeutic strategy to suppress pathogenic T cells while not interfering with myeloid cell functions required for innate immunity.
| S-EPMC4506881 | biostudies-literature
Project description:Ion channels control sperm navigation within the female reproductive tract and, thus, are critical for their ability to find and fertilize an egg. The flagellar calcium channel CatSper controls sperm hyperactivated motility and is dependent on an alkaline cytoplasmic pH. The latter is accomplished by either proton transporters or, in human sperm, via the voltage-gated proton channel Hv1. To provide concerted regulation, ion channels and their regulatory proteins must be compartmentalized. Here, we describe flagellar regulatory nanodomains comprised of Hv1, CatSper, and its regulatory protein ABHD2. Super-resolution microscopy revealed that Hv1 is distributed asymmetrically within bilateral longitudinal lines and that inhibition of this channel leads to a decrease in sperm rotation along the long axis. We suggest that specific distribution of flagellar nanodomains provides a structural basis for the selective activation of CatSper and subsequent flagellar rotation. The latter, together with hyperactivated motility, enhances the fertility of sperm.
| S-EPMC6177234 | biostudies-literature
Project description:Intracellular calcium ([Ca2+]i) is a basic and ubiquitous cellular signal controlling a wide variety of biological processes. A remarkable example is the steering of sea urchin spermatozoa towards the conspecific egg by a spatially and temporally orchestrated series of [Ca2+]i spikes. Although this process has been an experimental paradigm for reproduction and sperm chemotaxis studies, the composition and regulation of the signalling network underlying the cytosolic calcium fluctuations are hitherto not fully understood. Here, we used a differential equations model of the signalling network to assess which set of channels can explain the characteristic envelope and temporal organisation of the [Ca2+]i-spike trains. The signalling network comprises an initial membrane hyperpolarisation produced by an Upstream module triggered by the egg-released chemoattractant peptide, via receptor activation, cGMP synthesis and decay. Followed by downstream modules leading to intraflagellar pH (pHi), voltage and [Ca2+]i fluctuations. The Upstream module outputs were fitted to kinetic data on cGMP activity and early membrane potential changes measured in bulk cell populations. Two candidate modules featuring voltage-dependent Ca2+-channels link these outputs to the downstream dynamics and can independently explain the typical decaying envelope and the progressive spacing of the spikes. In the first module, [Ca2+]i-spike trains require the concerted action of a classical CaV-like channel and a potassium channel, BK (Slo1), whereas the second module relies on pHi-dependent CatSper dynamics articulated with voltage-dependent neutral sodium-proton exchanger (NHE). We analysed the dynamics of these two modules alone and in mixed scenarios. We show that the [Ca2+]i dynamics observed experimentally after sustained alkalinisation can be reproduced by a model featuring the CatSper and NHE module but not by those including the pH-independent CaV and BK module or proportionate mixed scenarios. We conclude in favour of the module containing CatSper and NHE and highlight experimentally testable predictions that would corroborate this conclusion.
| S-EPMC7067495 | biostudies-literature
Project description:BACKGROUND:Cilia and the sperm flagellum share many structural properties. Meiosis-specific nuclear structural 1 (MNS1) is a recently characterized protein that is abundantly expressed in post-meiotic spermatids and is required for proper flagellar and motile cilia formation. To explore the possible functions of MNS1, we performed a BLAST search and determined it is homologous to the conserved domain pfam13868, exemplified by mitostatin. This protein interacts with mitofusin 2 (MFN2), a protein that participates in regulating mitochondrial associations to subcellular organelles. We hypothesized that an association between MFN2 and MNS1 in the sperm is involved in flagellar biogenesis and function. RESULTS:In the studies reported here, MFN2 was found in murine reproductive and somatic tissues high in ciliary content while MNS1 was present as two closely migrating bands in reproductive tissues. Interestingly, mitostatin was also present in reproductive tissues. Similar to Mns1 and mitostatin, Mfn2 was expressed in the testis as detected by RT-PCR. In addition, Mfn2 and Mns1 decreased in expression from pachytene spermatocytes to condensing spermatids as assessed by quantitative RT-PCR. Co-immunoprecipitation demonstrated an association between MFN2 and MNS1 in spermatogenic cells. Indirect immunofluorescence indicated that MFN2 and MNS1 co-localized to the sperm flagellum in freshly collected cauda epididymal sperm. MFN2 associated with the midpiece while MNS1 was present throughout the sperm tail in caput and cauda epididymal sperm. In spermatogenic cells, MFN2 was seen in the mitochondria, and MNS1 was present throughout the cell cytoplasm. MFN2 and MNS1 were present in detergent-resistant flagellar structures of the sperm. CONCLUSIONS:These results demonstrate that MFN2 and MNS1 are present in spermatogenic cells and are an integral part of the sperm flagellum, indicating they play a role in flagellar biogenesis and/or function.
| S-EPMC4038059 | biostudies-literature
Project description:Catsper1 is a voltage-gated calcium channel located in the plasma membrane of the sperm tail and is necessary for sperm motility and fertility in mice. We here examine the evolutionary pattern of Catsper1 from nine species of the rodent subfamily Murinae of family Muridae. We show that the rate of insertion/deletion (indel) substitutions in exon 1 of the gene is 4-15 times that in introns or neutral genomic regions, suggesting the presence of strong positive selection that promotes fixations of indel mutations in exon 1. The number of indel polymorphisms within species appears higher than expected from interspecific comparisons, although there are too little data to provide a statistically significant conclusion. These results, together with an earlier report in primates, indicate that positive selection promoting length variation in Catsper1 may be widespread in mammals. A structural model of Catsper1 suggested the importance of the exon 1-encoded region in regulating channel inactivation, which may affect sperm mobility and sperm competition. Our findings provide a necessary foundation for future experimental investigations of Catsper1's function in sperm physiology and role in sperm competition using rodent models.
| S-EPMC1351353 | biostudies-literature
Project description:TRPC proteins form cation conducting channels regulated by different stimuli and are regulators of the cellular calcium homeostasis. TRPC are expressed in cardiac cells including cardiac fibroblasts (CFs) and have been implicated in the development of pathological cardiac remodeling including fibrosis. Using Ca2+ imaging and several compound TRPC knockout mouse lines we analyzed the involvement of TRPC proteins for the angiotensin II (AngII)-induced changes in Ca2+ homeostasis in CFs isolated from adult mice. Using qPCR we detected transcripts of all Trpc genes in CFs; Trpc1, Trpc3 and Trpc4 being the most abundant ones. We show that the AngII-induced Ca2+ entry but also Ca2+ release from intracellular stores are critically dependent on the density of CFs in culture and are inversely correlated with the expression of the myofibroblast marker ?-smooth muscle actin. Our Ca2+ measurements depict that the AngII- and thrombin-induced Ca2+ transients, and the AngII-induced Ca2+ entry and Ca2+ release are not affected in CFs isolated from mice lacking all seven TRPC proteins (TRPC-hepta KO) compared to control cells. However, pre-incubation with GSK7975A (10 µM), which sufficiently inhibits CRAC channels in other cells, abolished AngII-induced Ca2+ entry. Consequently, we conclude the dispensability of the TRPC channels for the acute neurohumoral Ca2+ signaling evoked by AngII in isolated CFs and suggest the contribution of members of the Orai channel family as molecular constituents responsible for this pathophysiologically important Ca2+ entry pathway.
| S-EPMC7072683 | biostudies-literature
Project description:Repetitive oscillations in cytoplasmic Ca2+ due to periodic Ca2+ release from the endoplasmic reticulum (ER) drive mammalian embryo development following fertilization. Influx of extracellular Ca2+ to support the refilling of ER stores is required for sustained Ca2+ oscillations, but the mechanisms underlying this Ca2+ influx are controversial. Although store-operated Ca2+ entry (SOCE) is an appealing candidate mechanism, several groups have arrived at contradictory conclusions regarding the importance of SOCE in oocytes and eggs. To definitively address this question, Ca2+ influx was assessed in oocytes and eggs lacking the major components of SOCE, the ER Ca2+ sensor STIM proteins, and the plasma membrane Ca2+ channel ORAI1. We generated oocyte-specific conditional knockout (cKO) mice for Stim1 and Stim2, and also generated Stim1/2 double cKO mice. Females lacking one or both STIM proteins were fertile and their ovulated eggs displayed normal patterns of Ca2+ oscillations following fertilization. In addition, no impairment was observed in ER Ca2+ stores or Ca2+ influx following store depletion. Similar studies were performed on eggs from mice globally lacking ORAI1; no abnormalities were observed. Furthermore, spontaneous Ca2+ influx was normal in oocytes from Stim1/2 cKO and ORAI1-null mice. Finally, we tested if TRPM7-like channels could support spontaneous Ca2+ influx, and found that it was largely prevented by NS8593, a TRPM7-specific inhibitor. Fertilization-induced Ca2+ oscillations were also impaired by NS8593. Combined, these data robustly show that SOCE is not required to support appropriate Ca2+ signaling in mouse oocytes and eggs, and that TRPM7-like channels may contribute to Ca2+ influx that was previously attributed to SOCE.
| S-EPMC5461193 | biostudies-literature
Project description:BACKGROUND: Competition between spermatozoa from rival males for success in fertilization (i.e., sperm competition) is an important selective force driving the evolution of male reproductive traits and promoting positive selection in genes related to reproductive function. Positive selection has been identified in reproductive proteins showing rapid divergence at nucleotide level. Other mutations, such as insertions and deletions (indels), also occur in protein-coding sequences. These structural changes, which exist in reproductive genes and result in length variation in coded proteins, could also be subjected to positive selection and be under the influence of sperm competition. Catsper1 is one such reproductive gene coding for a germ-line specific voltage-gated calcium channel essential for sperm motility and fertilization. Positive selection appears to promote fixation of indels in the N-terminal region of CatSper1 in mammalian species. However, it is not known which selective forces underlie these changes and their implications for sperm function. RESULTS: We tested if length variation in the N-terminal region of CatSper1 is influenced by sperm competition intensity in a group of closely related rodent species of the subfamily Murinae. Our results revealed a negative correlation between sequence length of CatSper1 and relative testes mass, a very good proxy of sperm competition levels. Since CatSper1 is important for sperm flagellar motility, we examined if length variation in the N-terminus of CatSper1 is linked to changes in sperm swimming velocity. We found a negative correlation between CatSper1 length and several sperm velocity parameters. CONCLUSIONS: Altogether, our results suggest that sperm competition selects for a shortening of the intracellular region of CatSper1 which, in turn, enhances sperm swimming velocity, an essential and adaptive trait for fertilization success.
| S-EPMC4041144 | biostudies-literature