Chapter 1: roles of caldesmon in cell motility and actin cytoskeleton remodeling.
Caldesmon (CaD) is a multimodular protein that regulates contractility and actin cytoskeleton remodeling in smooth muscle and nonmuscle cells. A single gene (CALD1) encodes high molecular mass CaD (h-CaD) and low molecular mass CaD (l-CaD) by alternative splicings. The h-CaD exclusively expresses in smooth muscle, whereas the l-CaD ubiquitously expresses in all cell types except skeletal muscle. The h-CaD/l-CaD ratio could be a marker for monitoring differentiating and pathological states of smooth muscles. The l-CaD associates with stress fibers and membrane ruffles in nonmuscle cells and with the actin core of podosomes in highly motile/invasive cells. Together with tropomyosin, CaD stabilizes actin filaments and inhibits actin-tropomyosin-activated myosin ATPase activity. This inhibition can be effectively released by Ca(2+)-calmodulin and/or by phosphorylation with various kinases. Through its interactions with a spectrum of actin-binding proteins, CaD modulates dynamics of cortical actin networks and stress fibers, which are essential to cell motility and cytoskeleton rearrangement. Regulation of CaD level and its activity may provide a novel strategy for gene therapy.
Department of Biology, University of Iowa, Iowa City, Iowa 52242, USA.
Jim Jung-Ching
JJ
Lin
Yan
Y
Li
Robbin D
RD
Eppinga
Qinchuan
Q
Wang
Jian-Ping
JP
Jin
D008841:Actin Cytoskeleton / Q000502:physiology*; D000595:Amino Acid Sequence; D000818:Animals; D002148:Calmodulin-Binding Proteins / Q000502:physiology*; D002465:Cell Movement / Q000502:physiology*; D003599:Cytoskeleton / Q000502:physiology*; D006801:Humans; D008969:Molecular Sequence Data; D017386:Sequence Homology, Amino Acid
D002148:Calmodulin-Binding Proteins