Kyphoscoliosis Peptidase (KY)

The ky transcript encodes a novel protein that is detected only in skeletal muscle and heart, and has a domain homologous to human transglutaminase. The mutation is a dinucleotide deletion affecting codon 24, leading to a premature stop codon at position 105.KY interacted with several sarcomeric cytoskeletal proteins including filamin C (FLNC) and the slow isoform of the myosin-binding protein C (MYBPC1). A role for KY in regulating filamin C function in vivo was supported by expression analysis of filamin C in the KY-null mouse mutant, where distinct irregular subcellular localization of filamin C was found in subsets of muscle fibers, which appeared to be a specific outcome of KY deficiency. In vitro assays showed that KY has protease activity, and specific degradation of filamin C by KY was shown in transfected cells.