Transfer of lipid across the cytoplasm is an essential process for intracellular lipid traffic. Lipid transfer proteins (LTPs) are defined by highly controlled in vitro experiments. The functional relevance of these is supported by evidence for the same reactions inside cells. Major advances in the LTP field have come from structural bioinformatics identifying new LTPs, and from the development of countercurrent models for LTPs. However, the ultimate aim is to unite in vitro and in vivo data, and this is where much progress remains to be made. Even where in vitro and in vivo experiments align, rates of transfer tend not to match. Here we set out some of the advances that might test how LTPs work.
LTPs facilitate the essential movement of lipid across aqueous spaces and are defined by in vitro experiments.
Recent developments include a novel concept of countercurrent lipid transfer and identification of additional LTP families by bioinformatics.
In vivo and in vitro data have yet to converge to one complete model.
Advances in in vitro characterisation of LTPs provide an opportunity to unite biochemical experimentation to cellular function.