Vimentin filaments

Richburg, J.H. Boekelheide, K. (1996) Mono-(2-ethylhexyl) phthalate rapidly alters both Sertoli cell vimentin filaments and germ cell apoptosis in young rat testes. Toxicol, appl. Pharmacol., 137, 42-50... 

Faigle, W., Colucci-Guyon, E., Louvard, D., Amigorena, S., and Galli, T. (2000). Vimentin filaments in fibroblasts are a reservoir for SNAP23, a component of the membrane fusion machinery. Mol. Biol. Cell 11, 3485-3494. 

Granger, B. L., and Lazarides, E. (1980). Synemin A new high molecular weight protein associated with desmin and vimentin filaments in muscle. Cell 22, 727-738. 

Intermediate filaments (10 nm) are intermediate in diameter between microtubules (25 nm) and actin filaments (7 nm). Intermediate filaments are classified into five groups cytokeratin, desmin, vimentin, neural, and glial filaments (for review, see Lazarides, 1980). In skeletal muscle, there are both desmin and vimentin filaments. 

Intermediate filaments are assemblies of intermediate filament proteins that provide mechanical strength to animal cells. Intermediate filaments include keratins, desmin filaments, vimentin filaments, nuclear lamins, and neurofilaments. The diameter of these filaments (about 10 nm) is intermediate between the thin actin filaments (about 7 nm) and the thicker microtubules (about 25 nm). Networks of cytoplasmic intermediate filaments are found throughout the cytoplasm of most animal cells, with some concentration around the nucleus. The lamin proteins make a network of intermediate filaments, the nuclear lamina, that lies just inside the nuclear membrane. 

Gabbiani G, Schmid E, Winter S, Chaponmer C, De Chastonay C, Vandekerckhove J, Weber K, Franke WW (1981) Vascular smooth muscle cells differ fi om other smooth muscle cells predominance of vimentin filaments and a specific a-type actin. Proc Natl Acad Sci USA 78 298-302... 

Intermediate filaments of 7-11 run diameter (Weber and Osborn 1982) of the vimentin type (Franks et al. 1979) are arranged immediately around the cell nucleus, while the remaining cytoplasm reveals only small amounts of 10 mn filaments, which usually do not extend up to the outer membrane of the mononuclear phagocyte (Cain et al. 1982, 1983). With increasing differentiation of monocytes into mature macrophages and epithelioid cell equivalents, a loosening up of the perinuclear vimentin filament network was observed. This development was associated with a straightening of the filaments, which could now be followed into the ectoplasm and into the cytoplasmic processes. 

The application of both crocidolite asbestos (10 pg/ml) and silicon carbide (50 pg/ml) affected the vimentin system of the Syrian hamster epithelial cell line (M3E3/C3) derived from the lung of a foetus on day 15 of gestation in a time-dependent manner (Aufderheide et al. 1994). The vimentin network, which normally appears as a filigree-like pattern throughout the cytoplasm, after exposure to asbestos for 38 h concentrated in bundles. Exposure to silicon carbide induced a concentration of vimentin filaments within the cells at the expense of the normally anastomosing network. 

Fig. 7. Fluorescence micrograph of a reovirus type 3-infected CV-1 cell demonstrating vimentin filament organization within viral inclusions. Cell was subjected to indirect immunofluorescence microscopy using antibody against vimentin (bar = 20 p,m). From Sharpe et al. (1982), by permission of Virology.

Sharpe, A. H., Chen, L. B., Murphy, J. R., and Fields, B. N., 1980, Specific disruption of vimentin filament organization in monkey kidney CV-1 cells by diphtheria toxin, exotoxin A, and cycloheximide, Proc. Natl. Acad. Sci. USA 77 7267. 

Tissue-specific intermediate filaments have been classified into vimentin filaments, glial filaments, neurofilaments, desmin filaments and cytokeratin filaments. Although each type of filament is composed of a different protein, the various proteins demonstrate remarkable sequence homology. Their functions are unknown. There are at least nine different proteins associated with intermediate filaments. 

Figure 27 Confocal vs. STED images of biopolymers. The images are vimentin filaments labeled with Atto532 in a fixed PtK cell in mowiol (size bar represents 1 gm).

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