Sperm's Secret Voltage Switch: Scientists Unlock The Mystery Of Motility
Arthur T Knackerbracket has processed the following story:
Researchers at Stockholm University have unveiled the hidden intricacies of how sperm go from passive bystanders to dynamic swimmers. This transformation is a pivotal step in the journey to fertilization, and it hinges on the activation of a unique ion transporter. Their research has been published in Nature.
Imagine sperm as tiny adventurers on a quest to reach the ultimate treasure, the egg. They don't have a map, but they make use of something even more extraordinary: chemo-attractants. These are chemical signals released by the egg that act as siren call, directing and activating the sperm. When these signals bind to receptors on the sperm's surface, it triggers a series of events, starting their movement towards the egg. And in this intricate scenario, one key player is a protein known as "SLC9C1."
It's exclusively found in sperm cells, and it is usually not active. However, when the chemo-attractants interact with the sperm's surface, everything changes.
[...] The activation of SLC9C1 is driven by a change in voltage that occurs when chemo-attractants attach to the sperm. To accomplish this, SLC9C1 uses a unique feature called a voltage-sensing domain (VSD). Typically, VSD domains are associated with voltage-gated ion channels. But in the case of SLC9C1, it's something truly exceptional in the realm of transporters.
Researchers, led by David Drew, have unveiled the secrets behind SLC9C1's inner workings and provides the first example of voltage-sensing domain activation of a transporter and its connection via an unusually long voltage-sensing (S4) helix.
[...] "Transporters work very differently than channels and, as such, the VSD is coupled to the sperm protein in a way that we have just never seen before, or even imagined. Its exciting to see how nature has done this and perhaps, in the future, we can learn from this to make synthetic proteins that can be turned-on by voltage or develop novel male contraceptives that work by blocking this protein," David Drew notes.
Journal Reference:
Yeo, H., Mehta, V., Gulati, A. et al. Structure and electromechanical coupling of a voltage-gated Na+/H+ exchanger. Nature (2023). https://doi.org/10.1038/s41586-023-06518-2
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