The regulation of the interaction between F-actin and muscle fructose 1,6-bisphosphatase.
Interaction between rabbit muscle fructose 1,6-bisphosphatase (FBPase) and rabbit muscle F-actin results in heterologous complex formation [A. Gizak, D. Rakus, A. Dzugaj, Histol. Histopathol. 18 (2003) 135]. Calculated on the basis of co-sedimentation-binding experiments and ELISA assay-binding constant (Ka) revealed that FBPase binds to F-actin with Ka equal to 7.4 x 10(4) M(-1). The binding is down-regulated by ligands interacting with the FBPase active site (fructose 6-phosphate, fructose 1,6-bisphosphate, fructose 2,6-bisphosphate) and with the FBPase allosteric inhibitory site (AMP). The binding and the kinetic data suggests that FBPase may bind F-actin using a bipartite motif which includes the amino acids residues involved in the binding of the substrate as well as of the allosteric inhibitor of the enzyme. The in situ co-localization experiment, in which FBPase was diffused into skinned muscle fibres pre-incubated with phalloidin (polymeric actin-interacting toxin), has shown that FBPase binds predominantly to the region of the Z-line.
Rakus
Darek
D
Department of Animal Physiology, Zoological Institute, University of Wroclaw, Cybulskiego 30, 50-205 Wroclaw, Poland.
Gizak
Agnieszka
A
Dzugaj
Andrzej
A
D000199:Actins / Q000737:chemistry*; D000495:Allosteric Site; D020816:Amino Acid Motifs; D000818:Animals; D001665:Binding Sites; D004305:Dose-Response Relationship, Drug; D005456:Fluorescent Dyes / Q000494:pharmacology; D006597:Fructose-Bisphosphatase / Q000737:chemistry*; D007700:Kinetics; D008024:Ligands; D018613:Microscopy, Confocal; D008958:Models, Molecular; D018482:Muscle, Skeletal / Q000378:metabolism; D009132:Muscles / Q000201:enzymology*; D010590:Phalloidine / Q000737:chemistry; D011485:Protein Binding; D011817:Rabbits; D055672:Static Electricity; D013696:Temperature
D000199:Actins; D005456:Fluorescent Dyes; D008024:Ligands; D010590:Phalloidine; D006597:Fructose-Bisphosphatase