Filamin-C; Muscle-specific filamin, which plays a central role in muscle cells, probably by functioning as a large actin-cross-linking protein. May be involved in reorganizing the actin cytoskeleton in response to signaling events, and may also display structural functions at the Z lines in muscle cells. Critical for normal myogenesis and for maintaining the structural integrity of the muscle fibers.

Nebulin; This giant muscle protein may be involved in maintaining the structural integrity of sarcomeres and the membrane system associated with the myofibrils. Binds and stabilize F-actin.

LIM domain-binding protein 3; May function as an adapter in striated muscle to couple protein kinase C-mediated signaling via its LIM domains to the cytoskeleton.

Myosin-binding protein C, slow-type; Thick filament-associated protein located in the crossbridge region of vertebrate striated muscle a bands. In vitro it binds MHC, F- actin and native thin filaments, and modifies the activity of actin- activated myosin ATPase. It may modulate muscle contraction or may play a more structural role; Belongs to the immunoglobulin superfamily. MyBP family.

Kelch-like protein 41; Involved in skeletal muscle development and differentiation. Regulates proliferation and differentiation of myoblasts and plays a role in myofibril assembly by promoting lateral fusion of adjacent thin fibrils into mature, wide myofibrils. Required for pseudopod elongation in transformed cells.

Calsequestrin-1; Calsequestrin is a high-capacity, moderate affinity, calcium- binding protein and thus acts as an internal calcium store in muscle. Calcium ions are bound by clusters of acidic residues at the protein surface, often at the interface between subunits. Can bind around 80 Ca(2+) ions. Regulates the release of lumenal Ca(2+) via the calcium release channel RYR1; this plays an important role in triggering muscle contraction. Negatively regulates store-operated Ca(2+) entry (SOCE) activity.

Troponin I, fast skeletal muscle; Troponin I is the inhibitory subunit of troponin, the thin filament regulatory complex which confers calcium-sensitivity to striated muscle actomyosin ATPase activity.

Kelch-like protein 40; Substrate-specific adapter of a BCR (BTB-CUL3-RBX1) E3 ubiquitin ligase complex that acts as a key regulator of skeletal muscle development. The BCR(KLHL40) complex acts by mediating ubiquitination and degradation of TFDP1, thereby regulating the activity of the E2F:DP transcription factor complex (By similarity). Promotes stabilization of LMOD3 by acting as a negative regulator of LMOD3 ubiquitination; the molecular process by which it negatively regulates ubiquitination of LMOD3 is however unclear (By similarity).