Substrate targeting component of a cullin-RING-based E3 ubiquitin-protein ligase complex RTT101(MMS1-CRT10). RTT101(MMS1-CRT10) may regulate nucleotide synthesis through transcriptional regulation of RNR genes encoding ribonucleotide reductases. Component of a cullin-RING ligase (CRL) composed of 4 subunits: the RING protein HRT1, the cullin RTT101, a linker protein MMS1, and the substrate receptor CRT10. Interacts with MMS1. By DNA damage and hydroxyurea (HU). Present with 125 molecules/cell in log phase SD medium.