A protein factor that regulates the length of R-actin. It is chemically similar, but immunochemically distinguishable from actin. (mesh:D000185)
| Synonym | Reference | Specificity |
| actinin | Exact |
| Identifier | Name | Relation |
| HGNC:166 | ACTN4 | isa |
| HGNC:165 | ACTN3 | isa |
| HGNC:164 | ACTN2 | isa |
| HGNC:163 | ACTN1 | isa |