Kelch-like protein 14 (KLHL14) belongs to the KLHL family []. Its is also known as printor (protein interactor of torsinA) and selectively binds to the ATP-free form, but not to the ATP-bound form of torsinA, suggesting a role for printor as a cofactor rather than a substrate of the AAA+ protein torsinA [].The KLHL (Kelch-like) proteins generally have a BTB/POZ domain, a BACK domain, andfive to six Kelch motifs. They constitute a subgroup at the intersection between the BTB/POZ domain and Kelch domain superfamilies. The BTB/POZ domain facilitates protein binding [], while the Kelch domain (repeats) form β-propellers. The Kelch superfamily of proteins can be subdivided into five groups: (1) N-propeller, C-dimer proteins, (2) N-propeller proteins, (3) propeller proteins, (4) N-dimer, C-propeller proteins, and (5) C-propeller proteins. KLHL family members belong to the N-dimer, C-propeller subclass of Kelch repeat proteins []. In addition to BTB/POZ and Kelch domains, the KLHL family members contain a BACK domain, first described as a 130-residue region of conservation observed amongst BTB-Kelch proteins []. Many of the Kelch-like proteins have been identified as adaptors for the recruitment of substrates to Cul3-based E3 ubiquitin ligases [, ].
