Heteropolymer filaments of vimentin and desmin in vascular smooth muscle tissue and cultured baby hamster kidney cells demonstrated by chemical crosslinking.

Abstract

Certain smooth muscle cells of blood vessel walls as well as cultured baby hamster kidney cells contain simultaneously two different intermediate-sized filament (IF) proteins, desmin and vimentin. We have examined the question of the occurrence ofboth proteins in the same IF by chemically crosslinking the single cysteine group present in each ofthem. Oxidative crosslinking of filaments present in cytoskeletal preparations with cupric ion complexes of 1,10-phenanthroline resulted in formation ofthree types ofdimers: vimentin-vimentin, desmin-desmin, and vimentin-desmin. These dimers were separated by NaDodSO4/ polyacrylamide gel electrophoresis and characterized by binding of specific antibodies, by one-and two-dimensional gel electrophoresis of monomers obtained after cleavage of the disulfide bond by thiol agents, and by mapping of radioiodinated tryptic peptides. The demonstration ofheterodimers ofvimentin and desmin in vascular smooth muscle tissue of cow and chicken and in baby hamster kidney cells shows that the two proteins can be integrated in the same IF and can be nearest neighbors, oriented with their cysteine residues in a mirror-image symmetry. The possible existence ofheteropolymer IF in other cell types is discussed.tin and desmin has also been reported for Z lines of developing and mature cross-striated muscle, but this is still subject to debate (2)(3)(4)(5)(13)(14)(15).

Expression of transfected vimentin genes in differentiating murine erythroleukemia cells reveals divergent cis-acting regulation of avian and mammalian vimentin sequences.

“…We presume that chicken and mouse vimentins copolymerize when they are coexpressed in undifferentiated cells; although our antibodies react with both chicken and mouse vimentin and hence are not capable of discriminating between the two molecules by immunofluorescence microscopy, copolymerization of vimentin and desmin, vimentin and glial fibrillary acidic protein, and vimentin and neurofilament protein has been described (35,75,76,82,83). As chicken vimentin-expressing MEL cells differentiate, the composition of intermediate filaments probably changes gradually frotn a mouse-chicken vimentin heteropolymer to a chicken vimentin homopolymer.…”

Desmin Aggregate Formation by R120G αB-Crystallin Is Caused by Altered Filament Interactions and Is Dependent upon Network Status in Cells

“…A human lens epithelial cell line H36 was selected because it expressed both sHSPs ( Figure 7B, lane 1). Vimentin is a natural assembly partner for desmin (Quinlan and Franke, 1982;Schweitzer et al, 2001) and in a rat model of cataractogenesis, desmin can be expressed in lens epithelial cells (Lovicu et al, 2002) showing that desmin transfection in these cells is still a mimic of a physiologically important situation.…”

“…A human lens epithelial cell line H36 was selected because it expressed both sHSPs ( Figure 7B, lane 1). Vimentin is a natural assembly partner for desmin (Quinlan and Franke, 1982;Schweitzer et al, 2001) and in a rat model of cataractogenesis, desmin can be expressed in lens epithelial cells (Lovicu et al, 2002) showing that desmin transfection in these cells is still a mimic of a physiologically important situation.MCF7 cells express keratins (K8, 18, and 19), but not type III IFs ( Figure 7B; Schweitzer et al, 2001). Despite the lack of a type III assembly partner, desmin was still able to form extensive filament networks in most (87%; Table 1) of the transfected cells ( Figure 8C), which is consistent with previous studies (Raats et al, 1990;Schweitzer et al, 2001).…”

The Cytological and Immunohistochemical Study of Septal Cells in the Rat Lung.

“…That is, some filaments are likely to be co-polymers of two different proteins. Co-polymerization of desmin and vimentin has been shown in developing skeletal muscle cells [23] and vascular cells by double-labeling immunoelectron microscopy [22] and by chemical cross-linking with bi-functional reagents [20]. The functional significance of co-polymerization is not known, but the present study presented another example that it occurs not only in muscle cells but also in non-muscle cells.…”