<i>Arginine Kinase 1</i> supports energy homeostasis in <i>Drosophila</i> flight muscle development

The useful part

by Maria Paula Zappia, Anton Westacott, Hannah Cooke, Rhianna Geary, Libby Travers, Lucia de Castro, Oliver Carty, Maxim V. Frolov In Drosophila, Arginine kinase 1 (Argk1) is involved in maintaining ATP homeostasis during bursts of activity in tissues with high and variable rates of energy turnover such as muscle. Argk1 is the sole phosphagen kinase with dynamic expression throughout flight muscle development.

How it works

• Therefore, our data reveal an essential role for Argk1 in flight muscle development, presumably by sustaining local ATP levels to meet the energetic demand to support myofibrillogenesis, muscle growt...
• However, its role beyond stress conditions is less understood.
• Depleting Argk1 specifically in the muscles lead to low ATP level and NAD + /NADH ratio, indicative of defects in energy homeostasis, and results in animal lethality.
• In the wing disc-associated myoblasts, Argk1 knockdown causes a reduction in cell size without changes in cell cycle progression.
• Single cell RNA-sequencing (scRNA-seq) revealed that the transcriptomes of undifferentiated and differentiating Argk1-depleted myoblasts are not significantly affected compared to control.

What to take from it

based on the marker expression and overall composition of scRNA-seq cell clusters, the early states of myoblasts differentiation are not severely disrupted in Argk1-depleted myoblasts. Nonetheless, Argk1 knockdown severely impacts later stages of muscle development. Remarkably, Argk1-depleted muscles completely lack spontaneous muscle contractions, which are required for proper sarcomere maturation in the formation of the indirect flight muscle.