Kelch-like family member 40 (KLHL40)

Kelch-like family member 40 (KLHL40) is a protein characterized by the presence of BTB/POZ, BACK, and Kelch repeat domains[1][3]. It primarily acts as a substrate-specific adapter for the BTB-CUL3-RBX1 E3 ubiquitin ligase complex and is a key regulator of skeletal muscle development[1][2]. KLHL40 promotes stabilization of muscle thin filament proteins nebulin (NEB) and leiomodin-3 (LMOD3), inhibiting their ubiquitination and preventing their proteasome-mediated degradation[2]. Unlike most BTB-Kelch proteins that drive substrate degradation, KLHL40 uniquely maintains thin filament protein levels, ensuring proper sarcomere structure and function[2]. Mutations in KLHL40 reduce NEB and LMOD3 abundance, causing sarcomere disruption and resulting in a severe form of nemaline myopathy characterized by profound muscle weakness and early lethality[1][2]. The gene is evolutionarily conserved and its dysfunction represents a rare but well-established cause of congenital myopathy. Currently, KLHL40 is not a drug target, but its molecular role makes it of interest for understanding muscle maintenance and related diseases[3].

Other names

Kelch-like protein 40KBTBD5Sarcosynapsinkelch repeat and BTB domain-containing protein 5nemaline myopathy type 8SRYPSYRPNEM8

no drugs, hence no mechanisms, but hypothetically, modulation could involve altering ubiquitination or stabilization of sarcomere proteins