F-box only protein 32 (FBXO32)

Atrogin-1 (FBXO32, also known as muscle atrophy F-box protein) is a muscle-specific F-box protein that serves as the substrate recognition component of an SCF (Skp1–Cullin–F-box) E3 ubiquitin ligase complex[1][2][4]. This complex mediates polyubiquitination and subsequent degradation of key muscle proteins, regulating proteostasis during muscle atrophy, cardiac hypertrophy, and in response to diverse catabolic stimuli[1][2][3][4]. Atrogin-1 is strongly induced in various models of muscle wasting, is necessary for most types of muscle atrophy, and is also expressed in cardiac muscle, where it represses hypertrophic signaling (notably by promoting proteasomal degradation of calcineurin A)[1]. Atrogin-1 participates in regulation of ER function via degradation of chaperones such as BiP[3], interacts with sarcomeric proteins, and its loss leads to altered muscle homeostasis, mitochondrial defects, and resistance to catabolic atrophy[3]. While it is considered a potential therapeutic target for muscle wasting and cardiac hypertrophy, there are currently no approved direct modulators in clinical use.

Other names

Atrogin-1Muscle atrophy F-box proteinFBXO32

E3 ubiquitin ligase activity: tags substrate proteins (e.g., calcineurin A, sarcomeric proteins, and possibly BiP/chaperones) for proteasomal degradation[1][2][3][4].