Plasminogen activator in differentiating mouse keratinocytes

Roslyn Rivkah Isseroff, N. E. Fusenig, D. B. Rifkin

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Abstract

The activity of the serine protease plasminogen activator (PA) was measured in cell lysates from primary mouse keratinocyte cultures as well as from a number of established mouse keratinocyte lines. Enzyme activity was generally higher in the transformed lines than in the primary cultures; however, among the lines tested, those that expressed the highest degree of morphologic differentiation had the highest levels of cell-associated PA. In both the normal (primary) and transformed (established) keratinocyte cultures, PA activity increased when cultures reached confluence and morphologic evidence of differentiation was noted. The highest specific activity of the enzyme was found in cells shed from differentiating cultures, which consisted predominantly of detergent-resistant cornified envelopes. As the cultures differentiated and these cells were shed from the culture surface, the total cell-associated PA activity of the culture decreased accordingly. In both the normal and transformed keratinocyte cultures, peak PA activity occurred at a time when DNA synthesis was declining. These findings indicate that as keratinocytes differentiate, their intracellular levels of PA increase. The modulation of those endogenous keratinocyte enzyme may play an important, although as yet undefined, role in the normal maturation and terminal differentiation of these cells.

Original languageEnglish (US)
Pages (from-to)217-222
Number of pages6
JournalJournal of Investigative Dermatology
Volume80
Issue number4
StatePublished - 1983
Externally publishedYes

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ASJC Scopus subject areas

  • Dermatology

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