title: Evolutionary conservation of physical and functional interactions between phospholipase D and actin.
abstract: Phospholipase D (PLD) enzymes from bacteria to mammals exhibit a highly conserved core structure and catalytic mechanism, but whether protein-protein interactions exhibit similar commonality is unknown. Our objective was to determine whether the physical and functional interactions of mammalian PLDs with actin are evolutionarily conserved among bacterial and plant PLDs. Highly purified bacterial and plant PLDs cosedimented with mammalian skeletal muscle alpha-actin, indicating direct interaction with F-actin. The binding of bacterial PLD to G-actin exhibited two affinity states, with dissociation constants of 1.13 pM and 0.58 microM. The effects of actin on the activities of bacterial and plant PLDs were polymerization dependent; monomeric G-actin inhibited PLD activity, whereas polymerized F-actin augmented PLD activity. Actin modulation of bacterial and plant PLDs demonstrated kinetic characteristics, efficacies, and potencies similar to those of human PLD1. Thus, physical and functional interactions between PLD and actin in PLD family members from bacteria to mammals are highly conserved throughout evolution.
authors.affiliation: Department of Internal Medicine, University of Iowa Carrer College of Medicine and VA Medical Center, Iowa City, IA 52242, USA. david-kusner@uiowa.edu
authors.forename: David J
authors.initials: DJ
authors.lastname: Kusner
authors.forename: James A
authors.initials: JA
authors.lastname: Barton
authors.forename: Chunbo
authors.initials: C
authors.lastname: Qin
authors.forename: Xuemin
authors.initials: X
authors.lastname: Wang
authors.forename: Shankar S
authors.initials: SS
authors.lastname: Iyer
mesh_terms: D000199:Actins / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D000818:Animals; D017360:Arabidopsis / Q000201:enzymology; D001665:Binding Sites; D005075:Biological Evolution; D001937:Brassica / Q000201:enzymology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D010739:Phospholipase D / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D011817:Rabbits; D013302:Streptomyces / Q000201:enzymology
chemical_list: D000199:Actins; D004791:Enzyme Inhibitors; D010739:Phospholipase D