Molecular diversity of cell-matrix adhesions

Eli Zamir*, Ben Zion Katz, Shin Ichi Aota, Kenneth M. Yamada, Benjamin Geiger, Zvi Kam

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

In this study we have examined for molecular heterogeneity of cell-matrix adhesions and the involvement of actomyosin contractility in the selective recruitment of different plaque proteins. For this purpose, we have developed a novel microscopic approach for molecular morphometry, based on automatic identification of matrix adhesions, followed by quantitative immunofluorescence and morphometric analysis. Particularly informative was fluorescence ratio imaging, comparing the local labeling intensities of different plaque molecules, including vinculin, paxillin, tensin and phosphotyrosine-containing proteins. Ratio imaging revealed considerable molecular heterogeneity between and within adhesion sites. Most striking were the differences between focal contacts, which are vinculin- and paxillin-rich and contain high levels of phosphotyrosine, and fibrillar adhesions, which are tensin-rich and contain little or no phosphotyrosine. Ratio imaging also revealed considerable variability in the molecular substructure of individual focal contacts, pointing to a non-uniform distribution of phosphotyrosine and the different plaque constituents. Studying the quantitative relationships between the various components of the submembrane plaque indicated that the levels of vinculin, paxillin and phosphotyrosine in adhesion sites are positively correlated with each other and negatively correlated with the levels of tensin. Tyrosine phosphorylation of focal contacts was highly sensitive to cellular contractility, and was diminished within 5 minutes after treatment with the kinase inhibitor H-7, an inhibitor of actomyosin contractility. This was followed by the loss of paxillin and vinculin from the focal adhesions. Tensin-rich fibrillar adhesions were relatively insensitive to H-7 treatment. These findings suggest a role for contractility in the generation of matrix adhesion diversity.

Original languageEnglish
Pages (from-to)1655-1669
Number of pages15
JournalJournal of Cell Science
Volume112
Issue number11
StatePublished - 1999
Externally publishedYes

Funding

FundersFunder number
National Institute of Dental and Craniofacial ResearchZIADE000525

    Keywords

    • Cell adhesion
    • Computerized microscopy
    • Focal contact
    • Ratio imaging

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