Cellular Microbodies

Caveolae

As technology devoted to microscopy and biochemistry is refined our understanding of the smallest organelles called microbodies has begun to unfold.

One important microbody is the caveola. Caveolae are invaginated, dynamic micro-domains in the plasma membrane. They are characterized by high levels of sphingolipids and cholesterol, and identified by the presence of the protein caveolin. They may play a crucial role in the organization of communication within cells.

Today's understanding of caveolae is based on two discoveries.

  1. receptor-mediated uptake of folate by caveolae
  2. caveolin, the first marker protein for caveolae which allow researchers to isolate it. (Miriam S. Hasson)

This small vesicle originating from the plasma membrane is implicated in a number of cellular processes including:

  • potocytosis - the novel process for the uptake of small molecules such as folate (Stephen W. Lacey)
  • signal transduction - caveolae are a rich in a variety of cell signaling molecules (Richard G. W. Anderson) For example:
    • regulation of insulin mediated events in fat cells - research has demonstrated that the insulin receptor is localized to caveolae micro-domains (Johanna Gustavsson)
  • mediation of cellular cholesterol movement into and out of cells
  • a target for multiple disease processes, including viruses, parasitic diseases, cancer, and heart disease.