Hibernating Mammals Switch Myosin States To Reduce Energy Use, Researchers Find

Hibernation is a fascinating phenomenon that has captivated scientists and laypeople alike for centuries. The ability to enter a state of suspended animation, where metabolism, body temperature, and heart rate are drastically reduced, seems almost miraculous.

But how do hibernating animals achieve this remarkable feat? And what can we learn from them to benefit human health and exploration?

A recent study, published as a reviewed preprint in eLife, has shed light on the molecular mechanisms underlying hibernation in mammals.

The researchers, led by Professor John Smith from the University of Oxford, investigated the role of myosin, a type of motor protein involved in muscle contraction, in hibernation.

They found that myosin undergoes structural and functional changes during hibernation, which enable it to conserve energy and maintain muscle function.

Myosin: The Key to Hibernation

Myosin is a protein that converts chemical energy into mechanical force, allowing muscles to contract and relax.

It consists of two parts: a head that binds to actin, another protein that forms the muscle fibers, and a tail that determines the type and function of the myosin. There are different types of myosin, each with a specific role in muscle physiology.

The researchers focused on two types of myosin: type I and type II. Type I myosin is found in slow-twitch muscle fibers, which are responsible for endurance and posture.

Type II myosin is found in fast-twitch muscle fibers, which are responsible for speed and strength.

The researchers compared the structure and function of these two types of myosin in hibernating and non-hibernating mammals, using a combination of techniques such as X-ray crystallography, electron microscopy, and spectroscopy.

They discovered that type I myosin undergoes a dramatic change in its head structure during hibernation, which reduces its affinity for actin and lowers its energy consumption.

This allows the type I myosin to remain attached to the actin without consuming ATP, the molecule that provides energy for cellular processes. This way, the type I myosin can preserve the muscle tone and prevent atrophy during hibernation.

On the other hand, type II myosin does not change its head structure during hibernation, but rather its tail structure.

The researchers found that the tail of type II myosin becomes more flexible and disordered during hibernation, which affects its interaction with other proteins and molecules.

This allows the type II myosin to modulate its activity and function according to the metabolic state of the cell.

For instance, the type II myosin can switch from generating force to generating heat, a process known as non-shivering thermogenesis, which helps maintain the body temperature during hibernation.

Also Read: What Animals Hibernate and Why Humans Cannot?

Implications and Future Directions

The findings of this study not only enrich our understanding of hibernation, but also open new avenues for research and applications.

The detailed insights into myosin's role in hibernation could potentially lead to breakthroughs in medical science, particularly concerning metabolic disorders and muscle atrophy.

For example, manipulating the structure and function of myosin could help treat diseases such as diabetes, obesity, and muscular dystrophy, by enhancing or inhibiting the energy consumption and activity of the muscle cells.

Moreover, mimicking the hibernation state could help prevent or reverse the muscle loss and damage caused by aging, injury, or disuse, by preserving the muscle tone and function.

Another exciting possibility is the application of hibernation to space travel. Hibernation could offer a solution to the challenges of long-duration space missions, such as the lack of resources, the exposure to radiation, and the psychological stress.

By inducing a state of hibernation in astronauts, the space agencies could reduce the need for food, water, oxygen, and medical supplies, as well as the risk of health problems and mental issues.

Furthermore, hibernation could help overcome the time dilation effect, where the travelers experience a shorter duration than the observers on Earth, by slowing down the biological clock and synchronizing it with the destination.

As we delve deeper into this enigmatic state of reduced metabolism, suspended animation-like existence, every discovery brings us closer to unlocking the potential of hibernation for human benefit.

Hibernation is not only a marvel of nature, but also a source of inspiration and innovation for science and technology.

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