Shedding light on the role of cAMP in mammalian sperm physiology

Balbach, Melanie; Beckert, Vera; Hansen, Jan N.; Wachten, Dagmar

doi:10.1016/j.mce.2017.11.008

Cited by 55 publications

(47 citation statements)

References 160 publications

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“…Optogenetic tools have been used in motile cilia, i.e. sperm flagella (Balbach et al, 2018, Jansen et al, 2015, where no specific targeting sequence is needed. When expressed under the control of the sperm-specific protamine-1 promoter, bPAC exclusively localized to sperm flagella and allowed to control sperm signaling and function by light (Jansen et al, 2015).…”

Section: Discussionmentioning

confidence: 99%

“…Optogenetics might be the key to overcome this issue, not least because it has already proven as a powerful method to manipulate and monitor cAMP dynamics in mouse sperm flagella, a specialized motile cilium (Balbach, Beckert et al, 2018, Jansen, Alvarez et al, 2015, Mukherjee, Jansen et al, 2016. The photo-activated adenylate cyclase bPAC (Stierl, Stumpf et al, 2011) has been employed to increase flagellar cAMP levels by blue light (Jansen et al, 2015), and the FRET-based cAMP biosensor mlCNBD-FRET has been used to monitor cAMP dynamics in sperm flagella (Mukherjee et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

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Nanobody-directed targeting of optogenetic tools to study signaling in the primary cilium

Hansen

Kaiser

Klausen

et al. 2020

Preprint

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Compartmentalization of cellular signaling forms the molecular basis of cellular behavior. Primary cilia constitute a subcellular compartment that orchestrates signal transduction independent from the cell body. Ciliary dysfunction causes severe diseases, termed ciliopathies. Analyzing ciliary signaling and function has been challenging due to the lack of tools to manipulate and analyze ciliary signaling in living cells. Here, we describe a nanobodybased targeting approach for optogenetic tools that allows to specifically analyze ciliary signaling and function, and that is applicable in vitro and in vivo. We overcome the loss of protein function observed after direct fusion to a ciliary targeting sequence, and functionally localize the photo-activated adenylate cyclase bPAC, the light-activated phosphodiesterase LAPD, and the cAMP biosensor mlCNBD-FRET to the cilium. Using this approach, we unravel the contribution of spatial cAMP signaling in controlling cilia length. Combining optogenetics with nanobody-based targeting will pave the way to the molecular understanding of ciliary function in health and disease.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Nanobody-directed targeting of optogenetic tools to study signaling in the primary cilium

Hansen

Kaiser

Klausen

et al. 2020

Preprint

Self Cite

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“…These signaling enzymes, protein phosphatase 1 (PP1), glycogen synthase kinase 3 (GSK3) and the calcium activated phosphatase (PP2B), affect sperm function in the epididymis and in the female reproductive tract. Several reviews detail the roles of sperm cAMP-PKA and calcium metabolism (Visconti et al, 2002;Burton and McKnight, 2007;Buffone et al, 2014;Stival et al, 2016;Freitas et al, 2017;Balbach et al, 2018;Leemans et al, 2019;Stewart and Davis, 2019). Following a brief summary of the actions of cAMP-PKA, calcium and pH, the remainder of the review will be focused largely devoted to examination of the key roles of PP1, GSK3, and calcium activated protein phosphatase, PP2B (PPP3R2/CC) in mediating the actions of the second messengers during sperm maturation and fertilization.…”

Section: Introductionmentioning

confidence: 99%

Signaling Enzymes Required for Sperm Maturation and Fertilization in Mammals

Dey

Brothag

Vijayaraghavan

2019

Front. Cell Dev. Biol.

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In mammals, motility and fertilizing ability of spermatozoa develop during their passage through the epididymis. After ejaculation, sperm undergo capacitation and hyperactivation in the female reproductive tract-a motility transition that is required for sperm penetration of the egg. Both epididymal initiation of sperm motility and hyperactivation are essential for male fertility. Motility initiation in the epididymis and sperm hyperactivation involve changes in metabolism, cAMP (cyclic adenosine monophosphate), calcium and pH acting through protein kinases and phosphatases. Despite this knowledge, we still do not understand, in biochemical terms, how sperm acquire motility in the epididymis and how motility is altered in the female reproductive tract. Recent data show that the sperm specific protein phosphatase PP1γ2, glycogen synthase kinase 3 (GSK3), and the calcium regulated phosphatase calcineurin (PP2B), are involved in epididymal sperm maturation. The protein phosphatase PP1γ2 is present only in testis and sperm in mammals. PP1γ2 has a isoform-specific requirement for normal function of mammalian sperm. Sperm PP1γ2 is regulated by three proteinsinhibitor 2, inhibitor 3 and SDS22. Changes in phosphorylation of these three inhibitors and their binding to PP1γ2 are involved in initiation and activation of sperm motility. The inhibitors are phosphorylated by protein kinases, one of which is GSK3. The isoform GSK3α is essential for epididymal sperm maturation and fertility. Calcium levels dramatically decrease during sperm maturation and initiation of motility suggesting that the calcium activated sperm phosphatase (PP2B) activity also decreases. Loss of PP2B results in male infertility due to impaired sperm maturation in the epididymis. Thus the three signaling enzymes PP1γ2, GSK3, and PP2B along with the documented PKA (protein kinase A) have key roles in sperm maturation and hyperactivation. Significantly, all these four signaling enzymes are present as specific isoforms only in placental mammals, a testimony to their essential roles in the unique aspects of sperm function in mammals. These findings should lead to a better biochemical understanding of the basis of male infertility and should lead to novel approaches to a male contraception and managed reproduction.

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“…In addition, the current perspective on sperm signalling points towards a compartmentalization of signalling along the flagellum, e.g. in the case of cAMP signalling (Balbach et al, 2017;Mukherjee et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

SpermQ - a simple analysis software to comprehensively study flagellar beating and sperm steering

Hansen

Rassmann

Jikeli

et al. 2018

Preprint

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Motile cilia, also called flagella, drive cell motility across a broad range of species; some cilia propel prokaryotes and eukaryotic cells like sperm, while cilia on epithelial surfaces create complex fluid patterns e.g. in the brain or lung. For sperm, the picture has emerged that the motile cilium, also called flagellum, is not only a motor, but also a sensor that detects stimuli from the environment, computing the beat pattern according to the sensory input. Thereby, the flagellum of the sperm cell navigates the sperm through a complex environment like the female genital tract. However, we know very little about how environmental signals change the flagellar beat and, thereby, the swimming behaviour of sperm. It has been proposed that distinct signalling domains in the flagellum control the flagellar beat. A detailed analysis has been mainly hampered by the fact that current comprehensive analysis approaches rely on complex microscopy and analysis systems. Thus, knowledge on sperm signalling regulating the flagellar beat is based on custom quantification approaches that are limited to only a few aspects of the flagellar beat, do not resolve the kinetics of the entire flagellum, rely on manual, qualitative descriptions, and are little comparable among each other. Here, we present SpermQ, a readyto-use and comprehensive analysis software to quantify sperm motility. SpermQ provides a detailed quantification of the flagellar beat based on common time-lapse images acquired by dark-field or epi-fluorescence microscopy, making SpermQ widely applicable. We envision SpermQ becoming a standard tool in flagellar and motile cilia research that allows to readily link studies on individual signalling components in sperm and distinct flagellar beat patterns.

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Shedding light on the role of cAMP in mammalian sperm physiology

Cited by 55 publications

References 160 publications

Nanobody-directed targeting of optogenetic tools to study signaling in the primary cilium

Nanobody-directed targeting of optogenetic tools to study signaling in the primary cilium

Signaling Enzymes Required for Sperm Maturation and Fertilization in Mammals

SpermQ - a simple analysis software to comprehensively study flagellar beating and sperm steering

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