caldesmon; CDM (CALD1, CAD, CDM)
Jump to navigation
Jump to search
Introduction
Function:
- actin- & myosin-binding protein implicated in regulation of actomyosin interactions in smooth muscle & nonmuscle cells (could act as a bridge between myosin & actin filaments)
- stimulates actin binding of tropomyosin which increases the stabilization of actin filament structure
- in muscle tissues, inhibits the actomyosin ATPase by binding to F-actin; this inhibition is attenuated by Ca+2-calmodulin & is potentiated by tropomyosin
- interacts with actin, myosin, two molecules of tropomyosin & with calmodulin
- binding to actin inhibited by Ca+2
- role during cellular mitosis & receptor capping
- in non-muscle cells, phosphorylation by CDC2 during mitosis causes caldesmon to dissociate from microfilaments
- phosphorylation reduces caldesmon binding to actin, myosin, & calmodulin & inhibits actomyosin ATPase activity
- phosphorylation occurs in both quiescent & dividing smooth muscle cells with similar effects on the interaction with actin & calmodulin & on microfilaments reorganization (putative)
Structure
- N-terminal part seems to be a myosin/ calmodulin-binding domain
- C-terminal part is a tropomyosin/actin/ calmodulin-binding domain
- these two domains are separated by a central helical region in the smooth-muscle form
- belongs to the caldesmon family
Compartment
- copurifies with CaM kinase-2
- in thin filaments in smooth muscle
- on stress fibers in fibroblasts (nonmuscle) (putative)
Alternative splicing
named isoforms=5
Expression
- high-molecular-weight caldesmon (isoform 1) is predominantly expressed in smooth muscles
- low-molecular-weight caldesmon (isoforms 2, 3, 4 & 5) are widely distributed in non-muscle tissues & cells
- not expressed in skeletal muscle or heart
Laboratory
More general terms
References
- ↑ UniProt http://www.uniprot.org/uniprot/Q05682.html
- ↑ Scott-Woo GC, Sutherland C, Walsh MP. Kinase activity associated with caldesmon is Ca2+/calmodulin- dependent kinase II. Biochem J. 1990 Jun 1;268(2):367-70. PMID: https://www.ncbi.nlm.nih.gov/pubmed/2163610
- ↑ Yamashiro S, Yamakita Y, Hosoya H, Matsumura F. Phosphorylation of non-muscle caldesmon by p34cdc2 kinase during mitosis. Nature. 1991 Jan 10;349(6305):169-72. PMID: https://www.ncbi.nlm.nih.gov/pubmed/1986309
- ↑ Entrez Gene http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=800