Substrate recognition component of a SCF (SKP1-CUL1-F-box protein) E3 ubiquitin-protein ligase complex which mediates the ubiquitination and subsequent proteasomal degradation of target proteins. Recognizes and directs ubiquitination of phosphorylated CLN1, CLN2 and GIC2. Probably constitutes the primary response element required for the generation or interpretation of the signal that induces glucose repression. Protein modification; protein ubiquitination. Interacts with SKP1. Component of the probable SCF(GRR1) complex containing CDC53, SKP1, RBX1 and GRR1. Associated with the particulate fraction. Probably forms a complex by protein-protein interactions via its leucine-rich segment. Expressed constitutively at low levels.