Protein-protein interactions in sperm and egg under the spotlight of super-resolution microscopy.

0482835 - BTÚ 2018 eng K - Conference Paper (Czech conference)
Dvořáková-Hortová, Kateřina - Děd, Lukáš - Šebková, Nataša - Frolíková, Michaela
Protein-protein interactions in sperm and egg under the spotlight of super-resolution microscopy.
[Superresolution and Life cell imaging symposium 2017. Vestec (CZ), 05.04.2017-07.04.2017]
R&D Projects: GA ČR GA14-05547S; GA MŠMT(CZ) ED1.1.00/02.0109
Institutional support: RVO:86652036
Keywords : CD46 * STED * acrosome reaction
OECD category: Biophysics

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. Protein CD46 is present on the acrosomal membrane of mouse sperm head and experiments with CD46-deficient mouse established the theory that CD46 participates in its stabilization. However, using super-resolution microscopy we demonstrated that CD46 is relocalizated during capacitation and acrosome reaction across the sperm head. This fact suggested that its role does not end by the loss of the acrosome and CD46 is probably a component of large multiprotein complex on sperm membrane that is responsible for sperm-egg interaction. The integrins are transmembrane proteins that participate in many cell-cell and cell-extracelular matrix interaction. The integrins are able to associate with other membrane receptors in multi-molecular complexes that participate in cell activation. Integrins are proteins consist of two different subunits α and β, when the β subunit is capable of binding to actin and controlling of its remodeling. The ability of β1 integrins to associate with CD46 is known from somatic cells. We showed that β1 integrins were present in acrosomal area of mouse sperm head and they were relocalized during capacitation and acrosome reaction similarly to CD46. Thanks to using STED and SIM super-resolution microscopy, we were able to distinguish mutual position of these protein in sperm head. This mutual position of CD46 and β1 integrins was investigated by colocalization analysis of super-resolution images and their association was confirmed by proximity ligation assay. Moreover, we presented that integrins α3 and α6 subunits were possibly pairing with β1, but occupying different compartments of the intact sperm head.
Permanent Link: http://hdl.handle.net/11104/0278508