Evidence for two interaction regions for phosphatidylinositol(4,5)-bisphosphate on mammalian profilin I.
The binding of phosphatidylinositol(4,5)-bisphosphate (PI(4,5)P(2)) to profilin at a region distinct from the actin interaction surface is demonstrated by experiments with covalently cross-linked profilin:beta-actin. The result is in agreement with observations made with several mutant profilins and provides strong evidence for two regions on mammalian profilin mediating electrostatic interaction with phosphatidylinositol lipids; one close to the binding site for poly(L-proline), and one partially overlapping with the actin-binding surface. Congruent with this, two plant profilins, which have a reduced number of positive amino acids in one of these regions, displayed a dramatically lower binding to PI(4,5)P(2) compared to human profilin I.
Skare
Petra
P
Department of Cell Biology, Wenner Gren Institute, Stockholm University, Sweden.
Karlsson
Roger
R
D000818:Animals; D017360:Arabidopsis / Q000235:genetics; D029681:Arabidopsis Proteins; D001665:Binding Sites; D003285:Contractile Proteins; D003432:Cross-Linking Reagents; D006801:Humans; D008322:Mammals; D008823:Micelles; D008840:Microfilament Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed; D019269:Phosphatidylinositol 4,5-Diphosphate / Q000378:metabolism*; D051304:Profilins; D017434:Protein Structure, Tertiary
D029681:Arabidopsis Proteins; D003285:Contractile Proteins; D003432:Cross-Linking Reagents; D008823:Micelles; D008840:Microfilament Proteins; C495746:PRF1 protein, Arabidopsis; D019269:Phosphatidylinositol 4,5-Diphosphate; D051304:Profilins