Membrane-associated actin in psoriatic epidermis

Microtubules (MT) occur in the keratinocytes as 20 nm broad tubular structures with an electron-lucent core surrounded by an electron-dense wall. The number and the length of the MT increased to the upper epidermal layers. In the normal keratinocytes the MT were relatively short (maximal length 2.2 microns) and slightly tortuous. Their outline was tenuous and irregular. Sometimes the MT were interrupted indicating a high fragility. In the upper layers of the psoriatic epidermis the MT reached a maximal length of 3.1 microns, showing a greater elongation than in the normal epidermis. The MT were stright and distinctly limited, most likely resulting from a higher grade of stabilization or polymerisation. By their interaction with the tonofilaments the MT may contribute to the stability of the cell shape, delaying the flattening of the psoriatic keratinocytes in the upper epidermal layers. Nowhere did the MT make direct contact with the cell membrane. At some places they did gain access to the cell membrane by short microfilaments.

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Fibronectin distribution in epithelial and associated tissues of the rat

Couchman

Gibson

Thom

et al. 1979

Arch Dermatol Res

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Specific antiserum was used to investigate the distribution of the extracellular glycoprotein, fibronectin, in rat skin and tongue tissue by light and electron microscopy with immunofluorescence and immunoperoxidase techniques. We conclude that fibronectin is absent from stable, differentiated parts of tissues, such as the sebaceous glands or the matrix, medulla, cortex, and cuticles of the hair and the inner and outer root sheaths, or even in tissues in which there is some cell movement, such as the epidermis. It is, however, characteristic of sites at which cell division is occurring in contact with an extracellular scaffolding, such as basement membrane or loose connective tissue. Conspicuous examples were in the glassy membrane and connective tissue sheath associated with the follicular epithelium, the basement membrane underlying vascular endothelial cells, the connective tissues surrounding and investing nerve and muscle fibre bundles, and the dermal connective tissue where fibronectin was often associated closely with collagen fibres. At the basement membrane of the dermal/epidermal junction, fibronectin occurred at the plasma membrane of the basal cells and in the lamina lucida area. There was no correlation with specific areas of cell-substrate adhesion, such as the hemidesmosomes. The endoplasmic reticulum of fibroblasts stained strongly suggesting that these cells represent a major site of synthesis.

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Membrane-associated actin in psoriatic epidermis

Cited by 3 publications

References 4 publications

Cyclic Nucleotides, Arachidonic Acid, and Polyamines in the Pathophysiology of Inflammatory Proliferative Skin Diseases

Cyclic Nucleotides, Arachidonic Acid, and Polyamines in the Pathophysiology of Inflammatory Proliferative Skin Diseases

Increased elongated and stabilized microtubules in psoriatic keratinocytes

Fibronectin distribution in epithelial and associated tissues of the rat

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