Scientists discover key muscle-forming protein responding to exercise and fasting

Researchers have discovered a new function of a protein that responds to exercise and intermittent fasting. This phosphatidylinositol-binding clathrin assembly protein (Picalm) is found in skeletal muscle and is essential for forming new muscle fibers.

“We have discovered that Picalm is an important component of the molecular adaptation mechanisms in muscle. It responds to training and fasting while also influencing the formation of new muscle fibers,” says paper co-author, Dr. Heike Vogel from the German Institute of Human Nutrition Potsdam-Rehbrücke (DIfE).

“In the long term, our findings could help to develop new approaches for the prevention and treatment of muscle loss in old age and metabolic diseases.”

Previous DIfE studies found that lifestyle interventions regulated Picalm in adipose tissue and influenced metabolic processes. The new Molecular Metabolism study combined various experimental approaches to investigate the role of Picalm in muscle.

The discovery is shared by researchers from the German Center for Diabetes Research partner institutions in mouse studies, a training study, and cell culture.

Animal test and muscle sample

The researchers analyzed several forms of intermittent fasting in mice, which showed Picalm expression increased in muscle tissue. A similar effect was also noted in mice that were made to regularly exercise.

In another approach, the team analyzed muscle samples from a training study at the University of Tübingen, Germany. The participants were overweight and completed a structured bicycle ergometer program. In this study, the team reported that Picalm expression increased after training.

Picalm’s mechanism involves cells taking up and transporting components such as epidermal growth factor.“The results indicate that Picalm plays an important role in how muscle cells adapt to changing living conditions,” says Vogel.

Cultured muscle cell test

In another experiment with muscle cells, the team evidenced that Picalm is essential for the formation of new muscle fibers from progenitor cells (myogenesis).

When Picalm expression was reduced, the researchers found that the cells developed significantly poorer into mature muscle fibers. They explain that this is caused by disturbances in fundamental cellular processes.

Picalm’s mechanism involves cells taking up and transporting components such as epidermal growth factor. However, if this process is disrupted, known as clathrin-mediated endocytosis, then it causes similar defects as a lack of Picalm.

Moreover, low Picalm also changed the composition of proteins on the cell surface while disrupting the organization of the actin cytoskeleton, the researchers highlight. They explain that this network is essential for cell shape, stability, and movement. This makes it crucial for the alignment and fusion of muscle progenitor cells into functioning muscle fibers.

Nutrition for muscle health

Industry developments in muscle health are expanding — recently, a randomized clinical trial showed that long-term supplementation with Sabinsa’s Sabeet significantly improves key markers of muscle quality and neuromuscular performance in postmenopausal women.

Another clinical study suggested that Balchem’s vitamin K2, K2Vital, may support neuromuscular signaling post-exercise in older adults. This pathway supports nerve-muscle communication and helps maintain muscle control. 

In innovations, AstaReal AB introduced a vegan vitamin D3+K2 supplement for bone, muscle & immune health, made from lichen.