The fusion of an ovum and a sperm relies on processes that remain largely unknown. But today, researchers have identified a complex interaction of proteins.
Illustrative image Pixabay
Thanks to an advanced version of AlphaFold, an artificial intelligence tool for protein modeling, a team has shed light on a protein trimer essential for fertilization. This complex plays a key role in the recognition between the ovum and sperm.
This discovery challenges a long-standing hypothesis that only two proteins present on both gametes were sufficient to ensure fertilization. The results show that three proteins, including the newly identified Tmem81, interact.
The researchers tested their predictions on several species. They observed this process in zebra fish, mice, and even human cells. This trimer, located on the sperm membrane, is crucial for gamete fusion.
In vertebrates, this interaction occurs via a specific ovular protein, called Juno in mammals and Bouncer in fish. These proteins allow the ovum to filter compatible spermatozoa.
The conservation of this mechanism over millions of years of evolution emphasizes its importance. However, ovular proteins differ from one species to another, an aspect that intrigues researchers.
Understanding these processes could lead to advances in infertility treatments and open new avenues for reproductive research.
What is a protein?
Proteins are essential molecules for the proper functioning of living organisms. Composed of chains of amino acids, they contribute to cell structure, biochemical reactions, and communication between cells. Each protein has a unique shape that allows it to perform specific functions.
Fertilization is the process by which a sperm fuses with an ovum to form a zygote. Researchers have discovered that a complex of three proteins (Izumo1, Spaca6, and Tmem81) is crucial at this stage, as it enables the binding between the sperm and ovum. Without this trimer, fertilization cannot occur, leading to sterility.
What is AlphaFold?
AlphaFold is an artificial intelligence tool developed by DeepMind, capable of predicting the three-dimensional structure of proteins based on their amino acid sequence. This modeling is essential for understanding how proteins function and their role in various biological processes, such as fertilization. The accuracy of AlphaFold has allowed researchers to solve biochemical puzzles that were previously difficult to tackle.
Article author: Cédric DEPOND