ATP5J

ATP5J Full Name

ATP synthase, H+ transporting, mitochondrial Fo complex, subunit F6

ATP5J Introduction

ATP5J, which has recently been officially re-designated as ATP5PF (ATP synthase peripheral stalk subunit F6), is a critical structural protein integral to mitochondrial energy metabolism. It is a fundamental component of the mitochondrial F1Fo-ATP synthase (Complex V), the massive multi-subunit enzyme complex responsible for producing the vast majority of cellular ATP via oxidative phosphorylation. Structurally, ATP5J constitutes subunit F6 of the membrane-spanning Fo complex. Its primary biological function is to serve as a crucial building block of the peripheral stalk—a rigid, stationary structure that acts as a physical "stator." This stator holds the catalytic F1 head securely in place while the central rotor, driven by the electrochemical proton gradient across the inner mitochondrial membrane, continuously spins to catalyze the conversion of ADP and inorganic phosphate into ATP. Without the stabilizing presence of ATP5J, the entire structural integrity of the ATP synthase complex fails, leading to a complete collapse of mitochondrial energy production.

Figure 1. Structural comparison of the bacterial and mitochondrial ATP synthase machinery. (Source: Ley-Ngardigal S, et al. 2022)

Intriguingly, beyond its canonical role inside the mitochondria, the ATP5J gene product also exists as a circulating vasoactive peptide known as coupling factor 6 (CF6). When released into the extracellular environment and the systemic bloodstream, CF6 acts as a potent vasoconstrictor. It binds directly to the surface of vascular endothelial cells, where it actively suppresses the production of vital endogenous vasodilators, specifically prostacyclin and nitric oxide. Consequently, elevated circulating levels of CF6 are heavily implicated in the pathogenesis of severe cardiovascular diseases. High plasma concentrations of this peptide are clinically correlated with essential hypertension, acute myocardial infarction, and early-stage cardiac systolic dysfunction.

In the field of oncology, ATP5J is increasingly recognized as a key player in tumor metabolic reprogramming. As cancer cells often dynamically shift their metabolic pathways to survive hostile, nutrient-deprived microenvironments, the efficient function of ATP synthase becomes paramount for biomass accumulation. Abnormal overexpression of ATP5J is frequently observed in various aggressive malignancies, notably colorectal cancer and non-small cell lung cancer (NSCLC). In NSCLC, aberrant oncogenic signaling rapidly accelerates ATP5J transcription, leading to enhanced mitochondrial ATP production that specifically fuels rapid tumor cell proliferation, cell migration, and acquired drug resistance. Because of its unique dual involvement in cardiovascular pathologies and cancer energy metabolism, ATP5J represents a highly compelling, multi-faceted target for pharmacological intervention.

Alternate Names for ATP5J

ATP5J; ATP synthase, H+ transporting, mitochondrial Fo complex, subunit F6; ATP synthase, H+ transporting, mitochondrial F0 complex, subunit F6; ATP5, ATP5A, ATPM; ATP synthase-coupling factor 6, mitochondrial; CF6; coupling factor 6; ATPase subunit F6; proliferation-inducing protein 36; mitochondrial ATP synthase, subunit F6

• 1. Ley-Ngardigal S, et al. Approaches to monitor ATP levels in living cells: where do we stand? FEBS J. 2022 Dec;289(24):7940-7969.
  2. Zeng QG, et al. Phosphorylation of POU3F3 Mediated Nuclear Translocation Promotes Proliferation in Non-Small Cell Lung Cancer through Accelerating ATP5PF Transcription and ATP Production. Adv Sci (Weinh). 2025 Apr;12(13):e2411503.