Changes in the distribution of actin-associated proteins in psoriatic keratinocytes. Immunohistochemical study using...

Recent studies support the presence of adherens junctions at the dermal-epidermal interface in addition to hemidesmosomes. In this area the integrin/actin-containing cytoskeleton connection occurs by means of a complex of proteins called actin-associated proteins (talin, vinculin, alpha-actinin). As previous studies have demonstrated the presence in psoriatic lesions of marked alterations in both the basement membrane molecular composition and the polarized expression of integrins, we decided to determine whether alterations in the behaviour of the actin-associated proteins could be demonstrated. We thus undertook an immunolocalization study with monoclonal antibodies directed against talin, vinculin, and alpha-actinin in cutaneous biopsies taken from involved and uninvolved skin of 12 patients with extensive chronic plaque psoriasis. The findings showed an almost total lack of reaction against talin and vinculin in the basal layer and an increased positivity against the proteins in the suprabasal layers. Similar, though less marked, alterations were present in uninvolved psoriatic skin. These results, in agreement with those of previous studies, confirm serious alterations in the matrix protein/cytoskeleton connection system, and support the hypothesis that this condition may play a key role in the pathogenesis of the disease.