Arkadia (RNF111) N-terminal-like PKA signaling regulator 2N (ARK2N) (ARK2N)

Arkadia (RNF111) N-terminal-like PKA signaling regulator 2N (ARK2N), also known as C18orf25, is a signaling protein that plays a pivotal role in skeletal muscle physiology and exercise capacity. It functions as a substrate for AMP-activated protein kinase (AMPK), and its phosphorylation is required for normal contraction-induced signaling and the maintenance of muscle fiber size. Studies in animal models have shown that the absence of ARK2N leads to reduced muscle fiber size, decreased contraction force, and impaired exercise capacity, suggesting its potential as a therapeutic target for muscle-wasting conditions such as sarcopenia and myopathies. The protein is characterized by its homology to the E3 ubiquitin ligase RNF111, although it lacks the domains necessary for ubiquitin binding, functioning instead as an adaptor or signaling protein. Genetic variants of ARK2N, such as the rs6507691 T allele, have been associated with increased gene expression and larger fast-twitch muscle fiber areas in elite strength athletes. Additionally, ARK2N acts as a transcription corepressor and is involved in the negative regulation of the Epstein-Barr virus (EBV) life cycle by interacting with JUN to inhibit the activation of the viral BZLF1 promoter. While no direct pharmacological modulators of ARK2N are currently available, its role in the AMPK pathway and its association with muscle performance make it a molecule of significant interest for metabolic and neuromuscular research.

Other names

C18orf25Arkadia-like protein 1ARKL1RNF111L1Chromosome 18 open reading frame 25

Regulation of skeletal muscle contractile function and exercise capacity through AMPK-mediated phosphorylation and downstream signaling pathways.