The chirality of phosphatidylserine and the activation of protein kinase C.
The properties of phosphatidyl-L-serine (L-PS) and phosphatidyl-D-serine (D-PS) were compared. The two forms of PS have similar but nonidentical L to L phase transition temperatures. Mixtures of phosphatidylserine with phosphatidylethanolamine and cholesterol (molar ratio 1:1:2) show polymorphic behavior at higher temperatures and in the presence of Ca2+. Mixtures with L-PS undergo conversion to nonlamellar phases at lower temperatures than do similar mixtures with D-PS. The aggregation of vesicles upon addition of histones is greater for L-PS than for D-PS. With fluorescence digital imaging microscopy we could show differences in the extent of formation of histone-induced domains enriched in PS or in diacylglycerol. The most enriched domains were induced with histone in membranes containing L-PS. The MARCKS peptide showed no differences in domain formation between L-PS and D-PS. The maximal activity of protein kinase C was greater in the presence of L-PS when histone, which could form more enriched domains, was the substrate. However, with a MARCKS peptide substrate, which formed domains of equal enrichment with L-PS and D-PS, the maximal activity of protein kinase C was the same with D-PS and with L-PS. These observations demonstrate that L-PS and D-PS have different physical properties. These differences likely contribute to the greater ability of L-PS to activate protein kinase C.
Department of Biochemistry, McMaster University Health Sciences Centre, Hamilton, Ontario, Canada.
R M
RM
Epand
C
C
Stevenson
R
R
Bruins
V
V
Schram
M
M
Glaser
D002152:Calorimetry, Differential Scanning; D004789:Enzyme Activation; D006657:Histones / Q000737:chemistry; D008027:Light; D008051:Lipid Bilayers / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D010718:Phosphatidylserines / Q000737:chemistry*; D010759:Phosphorus Isotopes; D011493:Protein Kinase C / Q000737:chemistry*; D012542:Scattering, Radiation; D013237:Stereoisomerism; D013379:Substrate Specificity
D006657:Histones; D008051:Lipid Bilayers; D010718:Phosphatidylserines; D010759:Phosphorus Isotopes; D011493:Protein Kinase C