Atrogin-1 (Atr1), also known as Muscle Atrophy F-box (MAFbx), is a member of SCF family of E3 ubiquitin ligases. It is expressed in heart and skeletal muscle. It is a critical component in the enhanced proteolysis leading to muscle atrophy in diseases such as diabetes, cancer and renal failure (1). Ubiquitin-dependent proteolysis regulates protein abundance and serves as a central regulatory control in many biological processes; it is mediated by the ubiquitin ligases, which represent a diverse family of proteins and protein complexes (2). A broad range of proteins involved in cell cycle progression, signal transduction, transcription, and development are ubiquitinated by the largest family of ubiquitin ligases, the SCF (Skp1, Cdc53/Cullin1, F-box protein) and SCF-like complexes. Among them, the F-box protein serves as the receptor for the target protein. Mice deficient in Atrogin-1/MAFbx were found to be resistant to atrophy, whereas overexpression of Atrogin-1/MAFbx suppressed MyoD-induced differentiation and inhibited myotube formation (3).

MyoD is required for myogenic stem cell function in adult skeletal muscle and it controls the identity and differentiation of myotube (4). Atrogin-1/MAFbx (Atr1) interacts with MyoD via an inverted LXXLL motif located in a series of helical leucine-charged residue-rich domains. Mutation in the LXXLL core motif represses ubiquitination and degradation of MyoD induced by Atrogin-1/MAFbx. This Atrogin-1 and MyoD interface mediates the binding to liganded nuclear receptors and promotes its degradation (5). Hence, up-regulation of Atrogin-1 in proliferating myoblasts antagonizes differentiation inducing MyoD degradation and preventing muscle-specific gene activation. Atrogin-1/MAFbx is approximately a 43kDa protein (355 amino acids).

The Atr1-selective antibodies were generated against purified Atrogin-1 protein (Atr1). Atr1-antibodies are affinity purified over immobilized antigen based chromatography, and the purified immunoglobulins are stabilized in antibody stabilization buffer. FabGennix Int. Inc., will also provide limited quantities of antigenic blocking protein for Atr1-101AP antibody. Antibodies to Atr1 (Atr1-101AP) will label ~43kDa protein in Western blot positive control samples for Atr1 and several other tissues.  FabGennix Inc. will also conjugate antibodies with secondary enzymes (alk-Pase or HRP) or fluorescent probes upon request at a nominal cost.

For research use only, not for diagnostic or therapeutic use.