Article

Title:Cofilin weakly interacts with 14-3-3 and therefore can only indirectly participate in regulation of cell motility by small heat shock protein HspB6 (Hsp20).
Authors:Sudnitsyna MV; Seit-Nebi AS; Gusev NB
Publication:Arch Biochem Biophys. 2012 May;521(1-2):62-70. doi: 10.1016/j.abb.2012.03.010. Epub 2012 Mar 19.
PubmedID22450169
Abstract
It has been previously reported that phosphorylated cofilin interacted with 14-3-3zeta protein to generate a sub-micromolar K(d) binary complex. Here we challenge this hypothesis by analyzing the direct association of recombinant cofilin with 14-3-3zeta using different in vitro biochemical methods. Phosphorylated cofilin at high concentration binds to 14-3-3 immobilized on nitrocellulose, however no complex formation was detected by means of native gel electrophoresis or chemical crosslinking. Intact dimeric or mutant monomeric 14-3-3 was unable to form stable complexes with phosphorylated or unphosphorylated cofilin detected by size-exclusion chromatography. In co-sedimentation assay 14-3-3 did not affect interaction of cofilin with F-actin. The data of native gel electrophoresis indicate that 14-3-3 did not affect interaction of cofilin with G-actin. Thus, cofilin only weakly interacts with 14-3-3 and therefore cannot directly compete with phosphorylated small heat shock protein HspB6 for its binding to 14-3-3. It is hypothesized that phosphorylated HspB6 might affect interaction of 14-3-3 with protein phosphatases (and/or protein kinases) involved in dephosphorylation (or phosphorylation) of cofilin and by this means regulate cofilin-dependent reorganization of cytoskeleton.