Cytoskeleton

The cytoskeleton is a system of fibers- and filaments located in the cytoplasm. Its functions are the transport of cellular structures, like for example mitochondria and vesicles, the anchoring of cell-organelles, and the maintenance of the cell shape and structure. The eukaryotic cytoskeleton consists of three main components, namely actin filaments, microtubules, and the intermediary filaments. Furthermore, there are a large number of proteins bound to these main components that fulfill various and diverse functions.

Actin filaments consist of the polymerized protein actin and are organized in a fibre-like double-helix structure with a diameter of approximately seven nanometers. They play an important role in stabilizing and altering the cell geometry and in the transport of vesicles. By binding to phalloidin, a substance from the group of pallotoxins, they can be labeled and detected by fluorescence microscopy. Microtubuli are dynamic and hollow cylinders of 25 nanometers diameter, which consist of polymers made up by tubulin subunits.

With their motorproteins dynesin and kinesin they allow intracellular transport over long distances and support the fixation of cell organelles. The intermediary filaments have structuring functions for the plasma membrane and the nucleus. There are six subtypes of the main components, namely sour and basic ceratin, desmins (GFAB, desmin, vimentin, peripherin), lamin (lamin A, lamin B and lamin C), and the neurofilaments (NF-L, internexin, NF-M, NF-A, nestin). Their diameter is intermediate between that of actin filamens and microtubli.

Hint: on antibodies-online.com you will find more than 1.100 antibodies specific for proteins of the cytoskeleton.