Substrate-recognition component of the cullin-RING-based CBC(fem-1) (Cul2-ElonginB-ElonginC) E3 ubiquitin-protein ligase complex of the DesCEND (destruction via C-end degrons) pathway, which recognizes a C-degron located at the extreme C terminus of target proteins, leading to their ubiquitination and degradation (By similarity). The C-degron recognized by the DesCEND pathway is usually a motif of less than ten residues and can be present in full-length proteins, truncated proteins or proteolytically cleaved forms (By similarity). Sex-determining protein; essential for the adoption of the male sexual fate in all tissues (PubMed:2317869). The CBC(fem-1) complex mediates the ubiquitination and subsequent proteasomal degradation of tra-1 (PubMed:17609115). Promotes ubiquitination and degradation of cdl-1 (PubMed:28118078). Protein modification; protein ubiquitination. Component of a complex containing fem-1, fem-2 and fem-3 (PubMed:23760267). Interacts with fem-2 (via N-terminus) and fem-3 (PubMed:17609115, PubMed:23760267). Component of the CBC(fem-1) E3 ubiquitin-protein ligase complex, at least composed of cul-2, elc-1, tra-1, fem-1, fem-2 and fem-3; mediates the ubiquitination and subsequent proteasomal degradation of tra-1 (PubMed:17609115). Interacts with cul-2 (PubMed:17609115). Interacts with tra-1 (PubMed:17609115). Interacts (via VHL-box motif) with elc-1 (PubMed:17609115). Interacts with sel-10 (PubMed:15306688). Interacts with ced-4 (PubMed:10764728). Belongs to the fem-1 family.