Addition of electrophilic lipids to actin alters filament structure.
Pathophysiological processes associated with oxidative stress lead to the generation of reactive lipid species. Among them, lipids bearing unsaturated aldehyde or ketone moieties can form covalent adducts with cysteine residues and modulate protein function. Through proteomic techniques we have identified actin as a target for the addition of biotinylated analogs of the cyclopentenone prostaglandins 15-deoxy-Delta(12,14)-PGJ(2) (15d-PGJ(2)) and PGA(1) in NIH-3T3 fibroblasts. This modification could take place in vitro and mapped to the protein C-terminal end. Other electrophilic lipids, like the isoprostane 8-iso-PGA(1) and 4-hydroxy-2-nonenal, also bound to actin. The C-terminal region of actin is important for monomer-monomer interactions and polymerization. Electron microscopy showed that actin treated with 15d-PGJ(2) or 4-hydroxy-2-nonenal formed filaments which were less abundant and displayed shorter length and altered structure. Streptavidin-gold staining allowed mapping of biotinylated 15d-PGJ(2) at sites of filament disruption. These results shed light on the structural implications of actin modification by lipid electrophiles.
Gayarre
Javier
J
Departamento de Estructura y Función de Proteínas, Centro de Investigaciones Biológicas, CSIC, 28040 Madrid, Spain.
Sánchez
David
D
Sánchez-Gómez
Francisco J
FJ
Terrón
María C
MC
Llorca
Oscar
O
Pérez-Sala
Dolores
D
D000199:Actins / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure*; D000818:Animals; D001665:Binding Sites; D051379:Mice; D018482:Muscle, Skeletal / Q000378:metabolism*; D041681:NIH 3T3 Cells; D015230:Prostaglandin D2 / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism; D011454:Prostaglandins A / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D011487:Protein Conformation; D011817:Rabbits
C477819:15-deoxyprostaglandin J2; D000199:Actins; D011454:Prostaglandins A; C100008:prostaglandin A2; D015230:Prostaglandin D2; C100573:prostaglandin A1