obscurin; obscurin-RhoGEF; obscurin-myosin light chain kinase; obscurin-MLCK (OBSCN, KIAA1556, KIAA1639)

Function

• role in myofibrillogenesis
• role in assembly of myosin into sarcomeric A bands in striated muscle
• isoform 3 together with ANK1 isoform Mu17/ank1.5 may provide a molecular link between the sarcoplasmic reticulum & myofibrils
• isoform 3 interacts with TTN/titin, ANK1 isoform Mu17/ank1.5, & with calmodulin (Ca+2-independent)

associates with fast skeletal muscle myosin (putative)

Cofactor: Mg+2 (putative)

Structure

• belongs to the protein kinase superfamily, CAMK Ser/Thr protein kinase family
• contains 1 DH (DBL-homology) domain
• contains 3 fibronectin F3 modules
• contains 55 Ig-like (immunoglobulin-like) domains
• contains 1 IQ domain
• contains 2 PH domains
• contains 2 protein kinase domains
• contains 1 SH3 domain

Compartment

• isoform 3: cytoplasm, myofibril, sarcomere, M line
• cytoplasm, myofibril, sarcomere, Z line
• in differentiating skeletal muscle cells, isoform 3 primarily localizes to the sarcomeric M-line & less frequently to the Z-disk
• isoform 3 colocalizes with ANK1 isoform Mu17/ank1.5 at the M-line in differentiated skeletal muscle cells

Alternative splicing

• named isoforms=5
• additional isoforms seem to exist

Notes

• isoform 3 lacks the kinase domain

More general terms

• cytoskeletal protein
• phosphoprotein

Additional terms

• myosin light chain kinase (MLCK, MYLK)

Database

• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=84033
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:84033
• OMIM: https://mirror.omim.org/entry/608616
• UniProt: http://www.uniprot.org/uniprot/Q5VST9.html