Which factor is directly linked to promoting mitochondrial biogenesis via transcriptional activators?

• A. NF-κB
• B. PGC-1a
• C. AMPK
• D. mTOR

Answer: (B)

PGC-1α is the central driver of mitochondrial biogenesis. It’s a transcriptional coactivator, not a DNA-binding factor itself, that teams up with transcription factors such as NRF-1, NRF-2, and TFAM to switch on the genes needed for mitochondrial proteins and mtDNA replication. When exercise or energy stress activates PGC-1α, it amplifies this transcriptional program, increasing both mitochondrial content and function. The other options either act in different pathways (NF-κB in inflammation), serve as upstream signals without directly driving the biogenesis transcriptional program (AMPK as an energy sensor that activates PGC-1α, not a transcriptional activator), or regulate growth and protein synthesis more broadly (mTOR) rather than directly promoting the mitochondrial biogenesis transcriptional cascade.