CBL/CAP Is Essential for Mitochondria Respiration Complex I Assembly and Bioenergetics Efficiency in Muscle Cells

Area of Science:

• Biochemistry
• Cell Biology
• Metabolic Research

Background:

• Cros-b-linker (CBL) is activated by insulin signaling.
• CBL depletion in mice improves insulin sensitivity, but mechanisms are unclear.
• The role of CBL in muscle mitochondrial function is not well understood.

Purpose of the Study:

• To investigate the role of CBL and its associated protein SORBS1/CAP in regulating mitochondrial function and metabolism in muscle cells.
• To elucidate the precise mechanisms by which CBL influences insulin sensitivity and glucose metabolism.

Main Methods:

• Independent depletion of CBL or SORBS1/CAP in cultured myocytes.
• Assessment of mitochondrial mass, proton leak, and respiratory complex I activity.
• Proteome profiling to analyze alterations in metabolic pathways.

Main Results:

• CBL- and CAP-depleted myocytes exhibited increased mitochondrial mass and proton leak.
• Mitochondrial respiratory complex I activity and respirasome assembly were reduced.
• Proteome analysis indicated changes in glycolysis and fatty acid degradation pathways.

Conclusions:

• The CBL/CAP pathway is crucial for linking insulin signaling to efficient mitochondrial respiration and metabolism in muscle.
• Dysregulation of this pathway may contribute to metabolic dysfunction.