ASB1 (ankyrin repeat and SOCS box containing 1) functions as a substrate recognition component of E3 ubiquitin ligase complexes, mediating targeted protein degradation through the ubiquitin-proteasome pathway 1. The protein forms complexes with ELOB to facilitate ubiquitination of specific substrates, including sulfide-quinone oxidoreductase (SQOR), enhancing K48-linked ubiquitination at lysine residues K207 and K344 to trigger proteasomal degradation 1. This mechanism is crucial for maintaining hydrogen sulfide homeostasis and redox balance in tissues. ASB1 plays a critical role in male fertility, as Asb1 knockout mice exhibit severe fertility impairment characterized by oligoasthenoteratozoospermia, excessive oxidative stress, decreased H2S levels, and severe sperm DNA damage 1. The protein shows tissue-specific expression patterns and stress responsiveness, with upregulated expression observed in murine models of acute social defeat stress 2. Clinically, ASB1 shows differential methylation patterns associated with anxiety disorders and ischemic cardiomyopathy, where specific methylation patterns correlate strongly with left ventricular ejection fraction and structural parameters 32. These findings suggest ASB1 functions as a stress-responsive regulatory protein with significant roles in reproductive health and cardiovascular disease.