Actomyosin cross-linking by caldesmon in non-muscle cells.
The role of myosin-binding in cytoskeletal arrangement of non-muscle low molecular weight caldesmon (l-caldesmon) was studied. The N-terminal myosin-binding domain of caldesmon N152 colocalized with myosin in transiently transfected chicken fibroblasts. When added exogenously to the Triton-insoluble cytoskeleton, N152 enhanced l-caldesmon displacement by exogenous C-terminal actin-binding fragment (H1). Thus, a significant fraction of l-caldesmon cross-links actin and myosin. In contrast, in epithelioid HeLa cells most of l-caldesmon was only actin-bound as H1 alone was enough for its displacement. Phosphorylation by mitogen-activated protein kinase reduced the capability of H1 to displace endogenous l-caldesmon, suggesting it may represent a regulatory mechanism for actin-caldesmon interaction in vivo.
Goncharova
E A
EA
Labouratory of Cell Motility, Institute of Experimental Cardiology Research Center, Moscow, Russia.
Shirinsky
V P
VP
Shevelev
A Y
AY
Marston
S B
SB
Vorotnikov
A V
AV
D000199:Actins / Q000378:metabolism; D000205:Actomyosin / Q000378:metabolism*; D000818:Animals; D001667:Binding, Competitive / Q000187:drug effects / Q000502:physiology; D002148:Calmodulin-Binding Proteins / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D002478:Cells, Cultured; D002645:Chickens; D003432:Cross-Linking Reagents / Q000494:pharmacology; D003599:Cytoskeleton / Q000378:metabolism; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism*; D006367:HeLa Cells / Q000166:cytology / Q000378:metabolism; D006801:Humans; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism / Q000494:pharmacology; D016297:Mutagenesis, Site-Directed; D009218:Myosins / Q000378:metabolism; D010446:Peptide Fragments / Q000235:genetics / Q000494:pharmacology; D010766:Phosphorylation / Q000187:drug effects; D017434:Protein Structure, Tertiary / Q000502:physiology; D014162:Transfection
D000199:Actins; D002148:Calmodulin-Binding Proteins; D003432:Cross-Linking Reagents; D010446:Peptide Fragments; D000205:Actomyosin; D020928:Mitogen-Activated Protein Kinases; D009218:Myosins