Lipid-associated proteins

Lipid-associated proteins are a relatively newly discovered class of proteins that are specifically associated with macromolecular lipid assemblies, other than bilayer membranes, in the cells of a wide range of organisms, from eubacteria to mammals. The vast majority of lipid-associated proteins in plants that have been described to date are intracellular. Oleosins are a class of relatively low molecular weight alkaline proteins of about 15–24 kDa that accumulate on the surfaces of lipid bodies in desiccation-tolerant seeds. Plastid lipid-associated proteins are localised exclusively in plastids and, like caleosins but unlike oleosins, they are not restricted to the Plantae but are also found in unicellular photosynthetic eukaryotes and homologues have even been found in cyanobacteria. The proteome of yeast lipid bodies has been systematically identified using electrospray mass spectrometry followed by an attempt at functional characterisation by deletion of the open reading frames corresponding to each identified protein.