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Updated: Aug 8, 2026

The c-FOS Protein Immunohistological Detection: A Useful Tool As a Marker of Central Pathways Involved in Specific Physiological Responses In Vivo and Ex Vivo
05:44

The c-FOS Protein Immunohistological Detection: A Useful Tool As a Marker of Central Pathways Involved in Specific Physiological Responses In Vivo and Ex Vivo

Published on: April 25, 2016

Viral and cellular fos proteins are complexed with a 39,000-dalton cellular protein

T Curran, C Van Beveren, I M Verma

    Molecular and Cellular Biology
    |January 1, 1985
    PubMed

    Insights

    Viral and cellular fos gene products (p55v-fos and p55c-fos) associate with a 39,000-dalton protein (p39). This protein (p39) forms a complex with p55, but its association differs between viral and cellular fos proteins.

    Area of Science:

    • Molecular Biology
    • Virology
    • Cellular Biology

    Background:

    • The fos gene family encodes oncoproteins involved in cellular regulation.
    • Viral (v-fos) and cellular (c-fos) fos gene products share significant sequence homology.
    • Understanding the structural differences and interactions of fos proteins is crucial for deciphering their biological roles.

    Purpose of the Study:

    • To investigate the structural differences between viral and cellular fos gene products.
    • To examine the association of fos proteins with a 39,000-dalton cellular protein (p39).
    • To elucidate the nature of the interaction between p39 and fos proteins.

    Main Methods:

    • Generation and purification of rabbit antisera against synthetic peptides specific to v-fos and conserved regions.
    • Immunoprecipitation assays using these antisera to detect and differentiate fos proteins and their associated factors.
    • Analysis of protein interactions under native and denaturing conditions.

    Main Results:

    • Antisera against a conserved region (M peptide) precipitated both p55v-fos and p55c-fos.
    • Antisera against a unique v-fos C-terminal region (V peptide) precipitated only p55v-fos, confirming distinct C termini.
    • Protein p39 was co-precipitated with both p55v-fos and p55c-fos by M peptide antisera, but not by V peptide antisera for p55c-fos.
    • Denaturation abolished p39 precipitation, indicating a non-covalent complex with p55, while p55v-fos precipitation was unaffected.

    Conclusions:

    • Viral and cellular fos proteins exhibit distinct C-terminal structures.
    • The 39,000-dalton cellular protein (p39) forms a complex with p55 (both viral and cellular fos products).
    • The interaction of p39 with p55c-fos is dependent on the native conformation of the protein, suggesting a specific binding interface.

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