Abstract

Vimentin IFs form close associations with the lipid droplets that are characteristic of adipose and steroidogenic cells. There is good evidence that changes in vimentin expression or organization can alter the metabolism of specific lipid components in cultured preadipose and adrenal cell lines. However, the effect of vimentin on triglyceride stability that is observed in preadipose cells is not obviously reflected in adrenal cells or fibroblasts. Conversely, an effect of vimentin on the metabolism of lipoprotein-derived cholesterol observed in adrenal cells is not apparent in preadipose cells. While the complexity of the phenotypes observed in these cells might be associated with cell-type-specific differences in the metabolism of triglycerides or lipoprotein-derived cholesterol, these studies have not yet revealed a general role of vimentin in lipid metabolism that would indicate a common mechanism in all cell types. A key issue that needs to be addressed is whether the effect of vimentin IFs on the stability of triglycerides or the trafficking of GSLs and lysosomal cholesterol is due to a direct participation of vimentin IFs in some aspect of these processes, or perhaps reflects an indirect response of the lipid metabolism of these cells to an effect of vimentin on some other cellular process.