Ankyrin repeat and SOCS box protein 9 (ASB9)

Ankyrin repeat and SOCS box protein 9 (ASB9) is a substrate-recognition component of the Cullin-RING E3 ubiquitin ligase complex, specifically the Elongin-Cullin-SOCS box-type (ECS/CRL5) E3 ligase. It contains an N-terminal intrinsically disordered region, an ankyrin repeat domain that binds substrate proteins, and a C-terminal SOCS box that mediates complex formation with Elongin B/C and Cullin 5. ASB9 binds to creatine kinase with high affinity, targeting it for ubiquitination and subsequent proteasomal degradation, which has roles in energy metabolism, cellular homeostasis, and possibly reproductive physiology[1][2][7][8]. There is currently no evidence of approved therapeutic drugs explicitly targeting ASB9, but its function as a molecular adaptor implicates it in pathways fundamental to cell function and disease.

Other names

Ankyrin repeat and SOCS box containing 9ASB-9DKFZP564L0862MGC4954FLJ20636ankyrin repeat and suppressor of cytokine signaling box protein 9testis tissue sperm-binding protein Li 57p

Ubiquitination of target proteins (e.g., creatine kinase) leading to their proteasomal degradation