title: Interaction of the C2 domain from protein kinase C(epsilon) with model membranes.
abstract: The C2 domain from protein kinase Cepsilon (PKCepsilon) binds to membranes but does not require Ca2+ to do so. This work examines the mode in which the conformation and organization of the phospholipids present in model membranes are altered by the presence of the C2 domain from PKCepsilon (C2-PKCepsilon). It is concluded from the results of differential scanning calorimetry that the protein shifted the temperature of the gel to the fluid phase transition of pure 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphate (POPA), widening the transition and increasing it to a higher temperature. When POPA was mixed with 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), the changes in the transition were smaller and no phase separation was observed. Experiments performed using magic angle spinning NMR showed that this C2 domain specifically affected POPA when the phospholipid was mixed with POPC, as indicated by the downfield shift in the isotropic resonance of POPA, the widening of the resonance peak, the decrease in T2, and the decrease in T1 observed at all temperatures. All these effects were quite marked compared with the very small effect observed with POPC, indicating the specificity of the effect. The presence of the C2-PKCepsilon protein changed the conformation of the polar head group of POPA, as shown by infrared spectroscopy. All these results clearly illustrate the electrostatic interaction that takes place between this C2 domain and membranes which contain POPA in the absence of Ca2+.
authors.affiliation: Departamento de Bioquímica y Biología Molecular (A), Facultad de Veterinaria, Universidad de Murcia, Apartado de Correos 4021, E-30080 Murcia, Spain.
authors.forename: Sonia
authors.initials: S
authors.lastname: Sánchez-Bautista
authors.forename: Ana
authors.initials: A
authors.lastname: de Godos
authors.forename: José A
authors.initials: JA
authors.lastname: Rodríguez-Alfaro
authors.forename: Alejandro
authors.initials: A
authors.lastname: Torrecillas
authors.forename: Senena
authors.initials: S
authors.lastname: Corbalán-García
authors.forename: Juan C
authors.initials: JC
authors.lastname: Gómez-Fernández
mesh_terms: D000818:Animals; D002152:Calorimetry, Differential Scanning; D008567:Membranes, Artificial; D019906:Nuclear Magnetic Resonance, Biomolecular; D010712:Phosphatidic Acids / Q000737:chemistry; D010713:Phosphatidylcholines / Q000737:chemistry; D010759:Phosphorus Isotopes; D051744:Protein Kinase C-epsilon / Q000737:chemistry*; D017434:Protein Structure, Tertiary; D021381:Protein Transport / Q000502:physiology; D051381:Rats; D013055:Spectrophotometry, Infrared; D055672:Static Electricity
chemical_list: C103238:1-palmitoyl-2-oleoyl-glycero-3-phosphatidic acid; D008567:Membranes, Artificial; D010712:Phosphatidic Acids; D010713:Phosphatidylcholines; D010759:Phosphorus Isotopes; D051744:Protein Kinase C-epsilon; C028694:1-palmitoyl-2-oleoylphosphatidylcholine