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Constitutive and regulated expression of vitronectin
D. Seiffert
Department of Vascular Biology, The Scripps Research Institute, La Jolla, United States of America
Offprint requests to: Dietmar Seiffert, M.D., DuPont Merck Pharmaceutical Company, Experimental Station, Bldg. 400. Wilmington, DE 19880-0400, USA
Summary. Tissue homeostasis depends on spatially and
temporally controlled expression of multifunctional
adhesive glycoproteins and their cellular counter
receptors , and on a tight regulation of proteolytic
enzyme systems. The adhesive glycoprotein vitronectin
(Vn) not only regulates adhesive events, but also controls
a number of these proteolytic enzyme cascades,
including the complement, coagulation, and fibrinolytic
systems. However, understanding of the biological
functions of this molecule is complicated due to it's
conformationally lability and its tendency to selfassociate.
While plasma Vn is monomeric and lacks
exposure of conformationally sensitive epitopes ,
platelet and tissue-associated Vn are believed to be
conformationally altered and multimeric. The latter
forms express a functional repertoire distinct from
plasma Vn. While little Vn immunoreactivity is
detectable in most normal tissues, increased depositions
of Vn have been observed in areas of tissue injury and
necrosis. Tissue Vn was believed to be plasma-derived,
but recent studies indicate that extrahepatic cells have
the biosynthetic potential to produce Vn and that its
synthesis can be regulated under inflammatory
conditions . Here, the constitutive and regulated
expression of Vn, its locations in tissues and interaction
with other matrix molecules are reviewed and their
implications for the functions of this molecule are
discussed. Histol Histopathol 12, 787-797
(1997)
Key words: Vitronectin, Extracellular matrix, Cell
adhesion, Proteolysis
DOI: 10.14670/HH-12.787
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