Substrate-recognition component of a Cul2-RING (CRL2) 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. 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. The CRL2(FEM1C) complex specifically recognizes proteins with an arginine at the C-terminus: recognizes and binds proteins ending with -Lys/Arg-Xaa-Arg and -Lys/Arg-Xaa-Xaa-Arg C-degrons, such as SIL1 or OR51B2, leading to their ubiquitination and degradation. The CRL2(FEM1C) complex mediates ubiquitination and degradation of truncated MSRB1/SEPX1 selenoproteins produced by failed UGA/Sec decoding. Protein modification; protein ubiquitination. Component of a CRL2 E3 ubiquitin-protein ligase complex, also named ECS (Elongin BC-CUL2/5-SOCS-box protein) complex, composed of CUL2, Elongin BC (ELOB and ELOC), RBX1 and substrate-specific adapter FEM1C. Widely expressed. Expressed at higher level in testis. The first seven ANK repeats at the N-terminus (1-242) are essnetial for recognition of Lys/Arg-Xaa-Arg and -Lys/Arg-Xaa-Xaa-Arg C-degrons. Insertion of the beta Geo promoter trap into the Fem1c gene is the cause of ROSA3 mice (PubMed:15082774). Adult ROSA3 mice exhibit widespread expression of the trap gene in epithelial cells found in most organs (PubMed:15082774). Although normal processing of the Fem1c transcript is disrupted in homozygous ROSA3 mice, some tissues show low levels of a partially processed transcript containing exons 2 and 3, which contain the entire coding region of Fem1c (PubMed:15082774). ROSA3 mice show no adverse effects in their sexual development or fertility or in the attenuation of neuronal cell death (PubMed:15082774). Belongs to the fem-1 family.