DAGs are lipid molecules capable of triggering a wide range of biological responses. Among others, they facilitate membrane fusion and they act as second messengers, predominantly by regulating both the translocation to the membrane compartment and the activation of C1 domain-bearing proteins . However, they have also been reported to be involved in ion channel activation, e.g. in the case of certain TRP (transient receptor potential) channels [2,3], the mechanism of which remains obscure.
We developed different, GROMOS-based sets of descriptions for biologically relevant DAG isoforms. We incorporated them at different concentrations into a model phosphatidylcholine bilayer system developed earlier , with small modifications. We subsequently employed Molecular Dynamics simulations of the mixed hydrated bilayer systems at the atomic level. The ensemble behavior of our systems was validated against experimental observations.
Our results provide detailed information about the impact of DAGs on the physical properties of phosphatidylcholine bilayers and highlight the local character of such modifications, e.g. in the form of structural defects. They contribute in elucidating certain underlying physical mechanisms of lipid-mediated signaling and provide clues in the context of determination of subtle biological distinction among different processes. Moreover, they give rise to reliable lipid models for investigating the interactions of membranes with specific lipid-sensing protein components.
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