Substrate-recognition component of a SCF-like ECS (Elongin-Cullin-SOCS-box protein) E3 ubiquitin-protein ligase complex which mediates the ubiquitination and subsequent proteasomal degradation of target proteins (By similarity). Mediates Notch-induced ubiquitination and degradation of substrates including E2A and JAK2 (By similarity). Required during embryonic heart development for complete heart looping (By similarity). Required for cardiomyocyte differentiation (By similarity). Involved in myogenic differentiation and targets filamin FLNB for proteasomal degradation but not filamin FLNA (By similarity). Also targets DES for proteasomal degradation (By similarity). Acts as a negative regulator of skeletal muscle mass (By similarity). Protein modification; protein ubiquitination. Component of a probable ECS E3 ubiquitin-protein ligase complex which contains CUL5, either RBX1 or RNF7/RBX2, Elongin BC complex (ELOB and ELOC) and ASB2. Interacts with SKP2. Through its interaction with SKP2, likely to bridge the formation of dimeric E3-ubiquitin-protein ligase complexes composed of an ECS complex and an SCF(SKP2) complex. Interacts with JAK2; the interaction targets JAK2 for Notch-mediated proteasomal degradation. Interacts with TCF3/E2A; the interaction is mediated by SKP2 and targets TCF3 for Notch-mediated proteasomal degradation (By similarity). Interacts with DES (By similarity). Localizes to the Z line in cardiomyocytes. The SOCS box domain mediates the interaction with the Elongin BC complex, an adapter module in different E3 ubiquitin-protein ligase complexes. The UIM domain is required for monoubiquitination. Monoubiquitinated. Belongs to the ankyrin SOCS box (ASB) family.