title: Membrane anchoring of diacylglycerol lactones substituted with rigid hydrophobic acyl domains correlates with biological activities.
abstract: Synthetic diacylglycerol lactones (DAG lactones) are effective modulators of critical cellular signaling pathways downstream of the lipophilic second messenger diacylglycerol that activate a host of protein kinase C (PKC) isozymes as well as other non-kinase proteins that share with PKC similar C1 membrane-targeting domains. A fundamental determinant of the biological activity of these amphiphilic molecules is the nature of their interactions with cellular membranes. This study characterizes the membrane interactions and bilayer anchoring of a series of DAG lactones in which the hydrophobic moiety is a 'molecular rod', namely a rigid 4-[2-(R-phenyl)ethynyl]benzoate moiety in the acyl position. Use of assays employing chromatic biomimetic vesicles and biophysical techniques revealed that the mode of membrane anchoring of the DAG lactone derivatives was markedly affected by the presence of the hydrophobic diphenyl rod and by the size of the functional unit at the terminus of the rod. Two primary mechanisms of interaction were observed: surface binding of the DAG lactones at the lipid/water interface and deep insertion of the ligands into the alkyl core of the lipid bilayer. These membrane-insertion properties could explain the different patterns of the PKC translocation from the cytosol to membranes that is induced by the molecular-rod DAG lactones. This investigation emphasizes that the side residues of DAG lactones, rather than simply conferring hydrophobicity, profoundly influence membrane interactions, and thus may further contribute to the diversity of biological actions of these synthetic biomimetic ligands.
authors: Department of Chemistry, Ben Gurion University, Beer Sheva, Israel.
authors: Or
authors: O
authors: Raifman
authors: Sofiya
authors: S
authors: Kolusheva
authors: Maria J
authors: MJ
authors: Comin
authors: Noemi
authors: N
authors: Kedei
authors: Nancy E
authors: NE
authors: Lewin
authors: Peter M
authors: PM
authors: Blumberg
authors: Victor E
authors: VE
authors: Marquez
authors: Raz
authors: R
authors: Jelinek
mesh_terms: D000818:Animals; D032701:Biomimetics; D055592:Biophysical Phenomena; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D020285:Cryoelectron Microscopy; D004075:Diglycerides / Q000138:chemical synthesis / Q000737:chemistry* / Q000378:metabolism*; D017261:Glycosylphosphatidylinositols / Q000737:chemistry / Q000378:metabolism; D057927:Hydrophobic and Hydrophilic Interactions; D007783:Lactones / Q000138:chemical synthesis / Q000737:chemistry* / Q000378:metabolism*; D008024:Ligands; D008563:Membrane Lipids / Q000737:chemistry* / Q000378:metabolism*; D015394:Molecular Structure; D011493:Protein Kinase C / Q000378:metabolism; D015290:Second Messenger Systems
chemical_list: D004075:Diglycerides; D017261:Glycosylphosphatidylinositols; D007783:Lactones; D008024:Ligands; D008563:Membrane Lipids; D011493:Protein Kinase C