Far from Inert: Membrane Lipids Possess Intrinsic Reactivity That Has Consequences for Cell Biology

Area of Science:

• Biochemistry
• Cell Biology
• Pharmacology

Background:

• Cellular membranes contain non-lipid constituents and ester-based lipids.
• The chemical reactivity between these components is not widely recognized.
• Lipidation reactions, where acyl groups transfer to non-lipids, are increasingly observed.

Purpose of the Study:

• To investigate the fundamental chemical reactivity between non-lipid membrane constituents and ester-based lipids.
• To explore the in vivo and in vitro significance of these lipidation reactions.
• To propose mechanisms for cellular protection against intrinsic lipidation and its toxic effects.

Main Methods:

• Utilizing model membranes to study lipidation reactions of peptides and organic molecules.
• Comparing in vitro lipidation product profiles with in vivo drug lipidation, such as propranolol.
• Assessing the lytic activity and in vitro toxicity of various compounds.

Main Results:

• Peptides and small organic molecules undergo lipidation in model membranes via direct acyl transfer.
• In vivo drug lipidation (e.g., propranolol) mirrors in vitro findings.
• Some compounds promote lipid hydrolysis, with higher in vivo lytic activity correlating to greater in vitro toxicity.

Conclusions:

• Intrinsic lipidation, a reaction between non-lipids and ester lipids, is a significant biochemical process.
• Deacylases and lipases are crucial for cellular defense against intrinsic lipidation.
• Intrinsic lipidation may contribute to drug toxicity and play a role in amyloid fibril nucleation.