Neuronal Membrane Lipids – Their Role in the Synaptic Vesicle Cycle
The synaptic vesicle cycle requires a stringent interplay between many entities, traversing through temporal and spatial coordination in order to ensure successful and sustainable neurotransmission. Adding to this complexity of coordination, the complete cycle of neuronal synapse is rapid, estimated at ∼1 min. As early as the 1960s, various studies have taken on the task to characterize the compositions of synaptic vesicles, identifying both lipids and proteins. Clearly, even till now, there have been extensive debates over how the synaptic vesicle (SV) cycle occurs, which led to various imaginable models, loosely divided into clathrin-dependent and -independent pathways. There have also been many lines of evidence to support the existence and relevance of each model, continuously adding to the wealth of knowledge in identifying the roles of various proteins in the SV cycle. However, less is known about the roles of lipids. While the most and best studied lipids are glycerophospholipids, in particular phosphorylated forms of glycerophosphatidylinositol, the phosphoinositides, we still do not know if and how other lipids, such as cholesterol and sphingolipids, regulate the SV cycle. This chapter will therefore focus on our current understanding of lipid involvement in the SV cycle. We will review the main classes of lipids found in SV membranes and discuss their functions in the context of the SV cycle.
KeywordsSynaptic Vesicle Membrane Fluidity Phosphatidic Acid Phosphatidic Acid Fatty Acyl Chain
List of Abbreviations:
inositol (1,4,5) triphosphate
niemann-pick disease type C
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