: fertilization, the culminating event in sexual reproduction, occurs when haploid sperm and egg recognize each other and fuse to form a diploid zygote. In mammals this process critically depends on the interaction between Izumo1, a protein exposed on the equatorial segment of acrosome-reacted sperm, and the egg plasma-membrane-anchored receptor Juno [1,2]. the molecular mechanism triggering gamete fusion is unresolved because both Izumo1 and Juno lack sequence similarity to known membrane fusogens. here we report the crystal structure of Izumo1, which reveals a membrane distal region composed of a four-helix bundle connected to a carboxy-terminal immunoglobulin (Ig)-like domain through a β-hairpin stabilized by disulfide bonds. remarkably, different regions of Izumo1 display significant structural similarities to two proteins expressed by the invasive sporozoite stage of plasmodium parasites: SPECT1, which is essential for host cell traversal and hepatocyte invasion [3]; and TRAP, which is necessary for gliding motility and invasion [4]. these observations suggest a link between the molecular mechanisms underlying host cell invasion by the malaria parasite and gamete membrane fusion at fertilization.

Nishimura, K., Han, L., Bianchi, E., Wright, G.j., de Sanctis, D., Jovine, L. (2016). The structure of sperm Izumo1 reveals unexpected similarities with Plasmodium invasion proteins. CURRENT BIOLOGY, 26(14) [10.1016/j.cub.2016.06.028].

The structure of sperm Izumo1 reveals unexpected similarities with Plasmodium invasion proteins

Bianchi, E.;
2016-01-01

Abstract

: fertilization, the culminating event in sexual reproduction, occurs when haploid sperm and egg recognize each other and fuse to form a diploid zygote. In mammals this process critically depends on the interaction between Izumo1, a protein exposed on the equatorial segment of acrosome-reacted sperm, and the egg plasma-membrane-anchored receptor Juno [1,2]. the molecular mechanism triggering gamete fusion is unresolved because both Izumo1 and Juno lack sequence similarity to known membrane fusogens. here we report the crystal structure of Izumo1, which reveals a membrane distal region composed of a four-helix bundle connected to a carboxy-terminal immunoglobulin (Ig)-like domain through a β-hairpin stabilized by disulfide bonds. remarkably, different regions of Izumo1 display significant structural similarities to two proteins expressed by the invasive sporozoite stage of plasmodium parasites: SPECT1, which is essential for host cell traversal and hepatocyte invasion [3]; and TRAP, which is necessary for gliding motility and invasion [4]. these observations suggest a link between the molecular mechanisms underlying host cell invasion by the malaria parasite and gamete membrane fusion at fertilization.
2016
Pubblicato
Rilevanza internazionale
Articolo
Esperti anonimi
Settore BIO/17
Settore BIO/11
English
Nishimura, K., Han, L., Bianchi, E., Wright, G.j., de Sanctis, D., Jovine, L. (2016). The structure of sperm Izumo1 reveals unexpected similarities with Plasmodium invasion proteins. CURRENT BIOLOGY, 26(14) [10.1016/j.cub.2016.06.028].
Nishimura, K; Han, L; Bianchi, E; Wright, Gj; de Sanctis, D; Jovine, L
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2108/359383
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