PKA activation in concert with ARIS and asterosap induces the acrosome reaction in starfish

Islam, M. Sadiqul; Kawase, Osamu; Hase, Sumitaka; Hoshi, Motonori; Matsumoto, Midori

doi:10.1017/s0967199406003881

Cited by 4 publications

(11 citation statements)

References 47 publications

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“…In a previous work, we found that EJ components are responsible for the elevation of intracellular cAMP in starfish spermatozoa and this cAMP subsequently enhanced the PKA activity [6]. Experiments with the PKA-specific antibody suggest a role for PKA on AR, as we have found an increased phosphorylation of some proteins ( Figure 3A).…”

Section: Effects Of Pka Inhibitors On the Kinase Activitysupporting

confidence: 67%

“…Sperm protein preparation was done as previously described [6]. Briefly, dry spermatozoa were diluted 1:3 (v/v) in ice-cold lysis buffer, and cells were lysed by a sonicator (Branson Sonifer 250, USA).…”

Section: Preparation Of Sperm Proteinmentioning

confidence: 99%

“…Protein kinase activity was assayed using fluorescent-tagged PKA-specific peptides as previously described [6]. Briefly, all reaction components were added on ice in a final volume of 25 μl of the following mixture: 5 μl of PepTag R PKA reaction buffer, 5 μl of PepTag R A1 (0.4 μg/μl), 5 μl of cAMP (5 μM), and 1-5 μl of sperm protein.…”

Section: Protein Kinase Assaymentioning

confidence: 99%

“…Among other changes, elevation of cGMP, cAMP, and increases in PKA (protein kinase A) activity also occur during AR [5,6]. This reaction is initiated when a spermatozoan interacts with egg-derived elements.…”

Section: Introductionmentioning

confidence: 99%

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Cyclic AMP-dependent PKA phosphorylates starfish sperm proteins during acrosome reaction

2007

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Abstract:The induction of acrosome reaction (AR) happens when starfish spermatozoa encounter the egg jelly (EJ). This complex process involves different signal transduction pathways, such as elevation of cAMP and the activation of protein kinase A (PKA). The specific inhibitors of PKA (H89 and KT5720) have been shown to inhibit the EJ-induced Ca 2+ elevation and AR. By using a Phospho-Ser/Thr PKA substrate antibody, we have detected an increased phosphorylation of 150, 200 and 220-kDa protein bands when starfish spermatozoa treated with EJ. The specific PKA inhibitors effectively inhibit phosphorylation of these proteins, suggesting an involvement of PKA on EJ-induced AR.

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Section: Effects Of Pka Inhibitors On the Kinase Activitysupporting

confidence: 67%

Section: Preparation Of Sperm Proteinmentioning

confidence: 99%

Section: Protein Kinase Assaymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Cyclic AMP-dependent PKA phosphorylates starfish sperm proteins during acrosome reaction

2007

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“…In a cAMP enzyme immunoassay, ARIS also increased [cAMP]i in the presence of seawater with high pH (pH 9.5, Islam et al, 2006b). Pretreatment of spermatozoa with two specific, cellpermeable PKA inhibitors, H89 and KT5720, prevented the induction of the AR in a concentration-dependent manner.…”

Section: Protein Kinase Activation Is Involved In Ar Inductionmentioning

confidence: 95%

Regulation of the starfish sperm acrosome reaction by cGMP, pH, cAMP and Ca2+

Matsumoto¹,

Kawase²,

Islam³

et al. 2008

Int. J. Dev. Biol.

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In the starfish, Asterias amurensis, three components in the jelly coat of eggs, namely acrosome reaction-inducing substance (ARIS), Co-ARIS and asterosap, act in concert on homologous spermatozoa to induce the acrosome reaction (AR). Molecular recognition between the sperm surface molecules and the egg jelly molecules must underlie signal transduction events triggering the AR. Asterosap is a sperm-activating molecule, which stimulates rapid synthesis of intracellular cGMP, pH and Ca 2+ . This transient elevation of Ca 2+ level is caused by a K + -dependent Na + /Ca 2+ exchanger, and the increase of intracellular pH is sufficient for ARIS to induce the AR. The concerted action of ARIS and asterosap could induce elevate intracellular cAMP levels in starfish sperm and the sustained increase in [Ca 2+ ], which is essential for the AR. The signaling pathway induced by these factors seems to be synergistically regulated to trigger the AR in starfish sperm.

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Protein kinase A activity leads to the extension of the acrosomal process in starfish sperm

Niikura

Alam

Naruse

et al. 2017

Molecular Reproduction Devel

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Acrosomal vesicles (AVs) of sperm undergo exocytosis during the acrosome reaction, which is immediately followed by the actin polymerization-dependent extension of an acrosomal process (AP) in echinoderm sperm. In the starfish Asterias amurensis, a large proteoglycan, acrosome reaction-inducing substance (ARIS), together with asteroidal sperm-activating peptide (asterosap) and/or cofactor for ARIS, induces the acrosome reaction. Asterosap induces a transient elevation of intracellular cGMP and Ca levels, and, together with ARIS, causes a sustained increase in intracellular cAMP and Ca . Yet, the contribution of signaling molecules downstream of cAMP and Ca in inducing AV exocytosis and AP extension remain unknown. A modified acrosome reaction assay was used here to differentiate between AV exocytosis and AP extension in starfish sperm, leading to the discovery that Protein kinase A (PKA) inhibitors block AP extension but not AV exocytosis. Additionally, PKA-mediated phosphorylation of target proteins occurs, and these substrates localize at the base of the AP, demonstrating that PKA activation regulates an AP extension step during the acrosome reaction. The major PKA substrate was further identified, from A. amurensis and Asterias forbesi sperm, as a novel protein containing six PKA phosphorylation motifs. This protein, referred to as PKAS1, likely plays a key role in AP actin polymerization during the acrosome reaction.

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PKA activation in concert with ARIS and asterosap induces the acrosome reaction in starfish

Cited by 4 publications

References 47 publications

Cyclic AMP-dependent PKA phosphorylates starfish sperm proteins during acrosome reaction

Cyclic AMP-dependent PKA phosphorylates starfish sperm proteins during acrosome reaction

Regulation of the starfish sperm acrosome reaction by cGMP, pH, cAMP and Ca2+

Protein kinase A activity leads to the extension of the acrosomal process in starfish sperm

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