| Domain | Name | Category | Type |
| IPR000731 | Sterol-sensing domain | Domain | Domain |
| IPR002202 | Hydroxymethylglutaryl-CoA reductase, class I/II | Family | Family |
| IPR004554 | Hydroxymethylglutaryl-CoA reductase, eukaryotic/archaeal type | Family | Family |
| IPR004816 | Hydroxymethylglutaryl-CoA reductase, metazoan | Family | Family |
| IPR009023 | Hydroxymethylglutaryl-CoA reductase, class I/II, NAD/NADP-binding domain superfamily | Family | Homologous superfamily |
| IPR009029 | Hydroxymethylglutaryl-CoA reductase, class I/II, substrate-binding domain superfamily | Family | Homologous superfamily |
| IPR023074 | Hydroxymethylglutaryl-CoA reductase, class I/II, catalytic domain superfamily | Family | Homologous superfamily |
| IPR023076 | Hydroxymethylglutaryl-CoA reductase, class I/II, conserved site | Site | Conserved site |
| IPR023282 | Hydroxymethylglutaryl-CoA reductase, N-terminal | Family | Homologous superfamily |