Structural analysis of a human glial variant laminin.

Astrocytes secrete laminin-like molecules in culture and may represent a major source of laminin in the developing central nervous system, yet these laminins have not been extensively characterized. We previously reported the presence of an astrocyte-derived variant laminin in media conditioned by human U251 MG astrocytoma cells. This laminin was partially purified in a highly anionic Mono Q fraction with strong adhesion activity for fibroblasts and glial cells (Aukhil et al.

Tenascin: does it play a role in epidermal morphogenesis and homeostasis?

Tenascin is a large glycoprotein of the extracellular matrix. Its complex multidomain structure, along with its unique distribution during embryogenesis, inflammation, wound healing, and tumorigenesis suggest this protein may play a significant role in regulating cell proliferation, migration, and differentiation. In this review I will summarize the structural features of tenascin and its localization in skin and discuss some of the potential roles of tenascin in the regulation of keratinocyte biology.

Epithelial cells are an important source of tenascin in normal and malignant human breast tissue.

The extracellular matrix glycoprotein tenascin is limited to the periductal matrix of normal breast tissue but is markedly increased in both malignant and fibroadenomatous proliferations. It has been hypothesized that the changes in tenascin expression in these tissues are the result of epithelial induction of tenascin expression by the underlying mesenchyme. We have used Western and Northern blotting techniques to examine tenascin expression by normal and malignant mammary epithelial cells in culture.

Tenascin expression in prostatic hyperplasia, intraepithelial neoplasia, and carcinoma.

The expression of tenascin, an extracellular matrix glycoprotein, was studied in three human prostatic carcinoma cell lines by Northern and Western blot analyses and in human prostate tissues by immunohistochemistry and Western blot analysis. All three carcinoma cell lines expressed tenascin mRNA and protein, which were found predominantly in secreted form in culture supernatant. By immunohistochemistry, fetal prostatic tissue showed strong and diffuse tenascin immunoreactivity around developing glands.

Divalent cation-dependent adhesion at the myotendinous junction: ultrastructure and mechanics of failure.

Junctional microfibrils, which span the lamina lucida of the vertebrate myotendinous junction, are thought to function in force transmission at the junction. This hypothesis has been tested by disrupting junctional microfibrils through elimination of extracellular divalent cations, and determining the effects of this treatment on the ultrastructure and mechanics of whole frog skeletal muscles passively stretched to failure. Muscles incubated in divalent cation-free solution failed exclusively in the lamina lucida of the myotendinous junction, while control muscles all failed within the muscle fibres, several millimetres away from the junction.