Kelch-like protein 41 (KLHL41), also known as sarcosin or Krp1, is involved in skeletal muscle development and differentiation [, ]. KLHL41 binds to Nebulin, an actin-binding protein that regulates the actin filament length. It also binds Nebulin-related anchoring protein (N-RAP), an actin-binding protein expressed in skeletal and cardiac muscle tissues [, ]. KLHL41 is localised between laterally fusing myofibrils in adult skeletal muscle and plays an important role for the correct functioning of adult skeletal muscle cells [].The KLHL (Kelch-like) proteins generally have a BTB/POZ domain, a BACK domain, and five 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 [, ].
The function of kelch repeat and BTB domain-containing protein 2 (KBTBD2) is not clear.The BTB superfamily includes KLHL (Kelch-like), KBTBD (Kelch repeat and BTB domain-containing), and KLHDC (Kelch domain-containing) subfamilies, which encompass structurally related molecules that differ in the types and numbers of their protein domains. The domain composition can appear to vary depending on the protein domain prediction program. For example, KLHL29, KLHL31, KLHL40, and KLHL41 were previously assigned within the KBTBD family as KBTBD9, KBTBD1, KBTBD5, and KBTBD10 respectively. KBTBD proteins have typically one BTB/POZ domain, occasionally a BACK domain, and two to four Kelch motifs [].
Kelch repeat and BTB domain-containing protein 3 (KBTBD3) belongs to the BTB/POZ domain containing family. Its function is not clear.The BTB superfamily includes KLHL (Kelch-like), KBTBD (Kelch repeat and BTB domain-containing), and KLHDC (Kelch domain-containing) subfamilies, which encompass structurally related molecules that differ in the types and numbers of their protein domains. The domain composition can appear to vary depending on the protein domain prediction program. For example, KLHL29, KLHL31, KLHL40, and KLHL41 were previously assigned within the KBTBD family as KBTBD9, KBTBD1, KBTBD5, and KBTBD10 respectively. KBTBD proteins have typically one BTB/POZ domain, occasionally a BACK domain, and two to four Kelch motifs [].
Kelch repeat and BTB domain-containing protein 8 (KBTBD8) belongs to the BTB-kelch protein family. KBTBD8 localises in the Golgi apparatus and translocates to the spindle apparatus during mitosis []. Its function is still not clear.The BTB superfamily includes KLHL (Kelch-like), KBTBD (Kelch repeat and BTB domain-containing), and KLHDC (Kelch domain-containing) subfamilies, which encompass structurally related molecules that differ in the types and numbers of their protein domains. The domain composition can appear to vary depending on the protein domain prediction program. For example, KLHL29, KLHL31, KLHL40, and KLHL41 were previously assigned within the KBTBD family as KBTBD9, KBTBD1, KBTBD5, and KBTBD10 respectively. KBTBD proteins have typically one BTB/POZ domain, occasionally a BACK domain, and two to four Kelch motifs [].
