Biomedical subjects

E E Weiss

Publications and source records attributed to E E Weiss.

3 recordsLinked to original sources

PubMed1998

Differential actin organization by vinculin isoforms: implications for cell type-specific microfilament anchorage.

Vinculin is found in all adherens junctions, while metavinculin, a larger splice variant, is coexpressed with vinculin only in smooth and cardiac muscle. To understand the significance of metavinculin expression, we compared ligand binding between turkey vinculin and metavinculin. Residues 1-258 were found essential for head-tail interactions in both proteins. The tail domains (VT and MVT, respectively) both bind to F-actin. However, while VT bundles F-actin, MVT generates highly viscous F-actin webs. In transfected PtK2 cells, VT causes F-actin needles or coils, while MVT-expressing cells display a diffuse F-actin distribution. Thus, the MVT-specific insert induces an F-actin supraorganization different from the VT-based form, suggesting that metavinculin has a specific role in muscle.

Actin Cytoskeleton↗

PubMed1998

Vinculin is part of the cadherin-catenin junctional complex: complex formation between alpha-catenin and vinculin.

In epithelial cells, alpha-, beta-, and gamma-catenin are involved in linking the peripheral microfilament belt to the transmembrane protein E-cadherin. alpha-Catenin exhibits sequence homologies over three regions to vinculin, another adherens junction protein. While vinculin is found in cell-matrix and cell-cell contacts, alpha-catenin is restricted to the latter. To elucidate, whether vinculin is part of the cell-cell junctional complex, we investigated complex formation and intracellular targeting of vinculin and alpha-catenin. We show that alpha-catenin colocalizes at cell-cell contacts with endogenous vinculin and also with the transfected vinculin head domain forming immunoprecipitable complexes. In vitro, the vinculin NH2-terminal head binds to alpha-catenin, as seen by immunoprecipitation, dot overlay, cosedimentation, and surface plasmon resonance measurements. The Kd of the complex was determined to 2-4 x 10(-7) M. As seen by overlays and affinity mass spectrometry, the COOH-terminal region of alpha-catenin is involved in this interaction. Complex formation of vinculin and alpha-catenin was challenged in transfected cells. In PtK2 cells, intact alpha-catenin and alpha-catenin1-670, harboring the beta-catenin- binding site, were directed to cell-cell contacts. In contrast, alpha-catenin697-906 fragments were recruited to cell-cell contacts, focal adhesions, and stress fibers. Our results imply that in vivo alpha-catenin, like vinculin, is tightly regulated in its ligand binding activity.

Animals↗

PubMed1987

[Perforating annular granuloma].

This study presents the first Venezuelan case of perforating granuloma annulare in an eleven year-old patient. The cutaneous eruption was characterized by minute lichenoid papules which have persisted for two years. These lesions were asymptomatic and most perforating, appearing in the dorsal side of hands and fingers. The histopathological study showed a classical granuloma annulare with sites of necrobiosis and perforation of the epithelium. This "transepithelial perforation" allows the elimination of collagen and cell detritus observed. The patient responds well to the injection of steroids into lesions.

Child↗