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Characterization of CD46 and β 1 integrin dynamics during sperm acrosome reaction

View Article: PubMed Central - PubMed

ABSTRACT

The acrosome reaction (AR) is a process of membrane fusion and lytic enzyme release, which enables sperm to penetrate the egg surroundings. It is widely recognized that specific sperm proteins form an active network prior to fertilization, and their dynamic relocation is crucial for the sperm-egg fusion. The unique presence of the membrane cofactor protein CD46 in the sperm acrosomal membrane was shown, however, its behaviour and connection with other sperm proteins has not been explored further. Using super resolution microscopy, we demonstrated a dynamic CD46 reorganisation over the sperm head during the AR, and its interaction with transmembrane protein integrins, which was confirmed by proximity ligation assay. Furthermore, we propose their joint involvement in actin network rearrangement. Moreover, CD46 and β1 integrins with subunit α3, but not α6, are localized into the apical acrosome and are expected to be involved in signal transduction pathways directing the acrosome stability and essential protein network rearrangements prior to gamete fusion.

No MeSH data available.


Percentage distribution of individual CD46 and β1 integrin relocation patterns among different times of capacitation and induced AR.Individual bars denote the percentage distribution of CD46 and β1 integrin staining patterns among individual times of capacitation and induced AR. Error bars denote SEM. AC – Acrosome Cap, rAC – residual Acrosome Cap, aES – apical Equatorial Segment, ES – Equatorial Segment, WSH – Whole Sperm Head. C – time of the capacitation, AR – time of the induced acrosome reaction.
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f2: Percentage distribution of individual CD46 and β1 integrin relocation patterns among different times of capacitation and induced AR.Individual bars denote the percentage distribution of CD46 and β1 integrin staining patterns among individual times of capacitation and induced AR. Error bars denote SEM. AC – Acrosome Cap, rAC – residual Acrosome Cap, aES – apical Equatorial Segment, ES – Equatorial Segment, WSH – Whole Sperm Head. C – time of the capacitation, AR – time of the induced acrosome reaction.

Mentions: Specific monoclonal antibodies (mAbs), see methods, were used to label the individual proteins and follow their localization over the sperm head. Epifluorescent microscopic observation detected distinct sperm head regions that showed a profound distribution of both proteins (Fig. 1) during the acrosome reaction, but not during the capacitation. However, the protein relocation depended on the length of capacitation, whether 60 or 90 minutes. When sperm were left to capacitate for 90 min, the protein relocation during acrosome reaction was faster compared to the group capacitated for only 60 min (Fig. 2). CD46 displayed five clearly distinct labelled regions, such as the acrosome cap, residual acrosome cap, apical equatorial segment, equatorial segment and the whole sperm head (Fig. 1A). For the β1 integrins, only three patterns could be followed, such as the acrosome cap, equatorial segment and whole sperm head (Fig. 1B, S1a,b).


Characterization of CD46 and β 1 integrin dynamics during sperm acrosome reaction
Percentage distribution of individual CD46 and β1 integrin relocation patterns among different times of capacitation and induced AR.Individual bars denote the percentage distribution of CD46 and β1 integrin staining patterns among individual times of capacitation and induced AR. Error bars denote SEM. AC – Acrosome Cap, rAC – residual Acrosome Cap, aES – apical Equatorial Segment, ES – Equatorial Segment, WSH – Whole Sperm Head. C – time of the capacitation, AR – time of the induced acrosome reaction.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5036054&req=5

f2: Percentage distribution of individual CD46 and β1 integrin relocation patterns among different times of capacitation and induced AR.Individual bars denote the percentage distribution of CD46 and β1 integrin staining patterns among individual times of capacitation and induced AR. Error bars denote SEM. AC – Acrosome Cap, rAC – residual Acrosome Cap, aES – apical Equatorial Segment, ES – Equatorial Segment, WSH – Whole Sperm Head. C – time of the capacitation, AR – time of the induced acrosome reaction.
Mentions: Specific monoclonal antibodies (mAbs), see methods, were used to label the individual proteins and follow their localization over the sperm head. Epifluorescent microscopic observation detected distinct sperm head regions that showed a profound distribution of both proteins (Fig. 1) during the acrosome reaction, but not during the capacitation. However, the protein relocation depended on the length of capacitation, whether 60 or 90 minutes. When sperm were left to capacitate for 90 min, the protein relocation during acrosome reaction was faster compared to the group capacitated for only 60 min (Fig. 2). CD46 displayed five clearly distinct labelled regions, such as the acrosome cap, residual acrosome cap, apical equatorial segment, equatorial segment and the whole sperm head (Fig. 1A). For the β1 integrins, only three patterns could be followed, such as the acrosome cap, equatorial segment and whole sperm head (Fig. 1B, S1a,b).

View Article: PubMed Central - PubMed

ABSTRACT

The acrosome reaction (AR) is a process of membrane fusion and lytic enzyme release, which enables sperm to penetrate the egg surroundings. It is widely recognized that specific sperm proteins form an active network prior to fertilization, and their dynamic relocation is crucial for the sperm-egg fusion. The unique presence of the membrane cofactor protein CD46 in the sperm acrosomal membrane was shown, however, its behaviour and connection with other sperm proteins has not been explored further. Using super resolution microscopy, we demonstrated a dynamic CD46 reorganisation over the sperm head during the AR, and its interaction with transmembrane protein integrins, which was confirmed by proximity ligation assay. Furthermore, we propose their joint involvement in actin network rearrangement. Moreover, CD46 and β1 integrins with subunit α3, but not α6, are localized into the apical acrosome and are expected to be involved in signal transduction pathways directing the acrosome stability and essential protein network rearrangements prior to gamete fusion.

No MeSH data available.