Differentiating cells of murine stratified squamous epithelia constitutively express plasminogen activator inhibitor type 2 (PAI-2)

Barbara C. Risse, Heather Brown, Robert M. Lavker, Julia M. Pearson, Mark S. Baker, David Ginsburg, Pamela J. Jensen*

*Corresponding author for this work

Research output: Contribution to journalArticle

26 Citations (Scopus)

Abstract

In stratified squamous epithelia a critical balance among cell proliferation, differentiation, and death must be maintained in order for these tissues to fulfill their barrier function. Previous studies have demonstrated that plasminogen activator inhibitor 2 (PAI-2) is a product of differentiating epidermal keratinocytes, suggesting a role for this inhibitor during squamous differentiation. Furthermore, in certain tumor cell lines, over-expression of PAI-2 confers resistance to the induction of programmed cell death, suggesting cytoprotective function(s). In the present study we demonstrate that PAI-2 mRNA and protein are constitutively and uniquely expressed in differentiating cells of murine stratified squamouS epithelia, including epidermis, esophagus, vagina, oral mucosa, and tongue. PAI-2 immunohistochemical localization patterns suggest a predominantly cytosolic distribution, consistent with biochemical identification of the major:PAI-2 species as a 43-kDa, presumably non-glycosylated protein. Functional analysis shows that the majority of epithelial PAI-2 is active. In contrast to the high levels of PAI-2 expression in stratified squamous epithelia, little or no PAI-2 is detectable in simple epithelia. These findings suggest that epithelial PAI-2 may mediate inhibition of intracellular proteinases associated with events during terminal differentiation and death that are unique to stratified squamous epithelia.

Original languageEnglish
Pages (from-to)559-569
Number of pages11
JournalHistochemistry and Cell Biology
Volume110
Issue number6
DOIs
Publication statusPublished - 1998
Externally publishedYes

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