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Dominant negative mutants of transforming growth factor-beta 1 inhibit the secretion of different transforming growth
A R Lopez1, J Cook, P L Deininger
1Department of Developmental Biology, Genentech Inc., South San Francisco, California 94080.
Abstract:
Transforming growth factor-beta (TGF-beta) is a secreted polypeptide factor that is thought to play a major role in the regulation of proliferation of many cell types and various differentiation processes. Several related isoforms have been structurally characterized, three of which, TGF-beta 1, -beta 2, and -beta 3, have been detected in mammalian cells and tissues. Each TGF-beta form is a homodimer of a 112-amino-acid polypeptide which is encoded as a larger polypeptide precursor. We have introduced several mutations in the TGF-beta 1 precursor domain, resulting in an inhibition of TGF-beta 1 secretion. Coexpression of these mutants with wild-type TGF-beta 1, -beta 2, and -beta 3 results in a competitive and specific inhibition of the secretion of different TFG-beta forms, indicating that these mutated versions act as dominant negative mutants for TGF-beta secretion. Overexpression of dominant negative mutants can thus be used to abolish endogenous secretion of TGF-beta and structurally related family members, both in vitro and in vivo, and to probe in this way the physiological functions of the members of the TGF-beta superfamily.
Insights
Researchers developed dominant-negative mutants to block transforming growth factor-beta (TGF-beta) secretion. This method allows for studying TGF-beta
Area of Science:
- Molecular Biology
- Cell Biology
- Biochemistry
Background:
- Transforming growth factor-beta (TGF-beta) is a crucial secreted polypeptide involved in cell proliferation and differentiation.
- Three mammalian isoforms (TGF-beta 1, -beta 2, -beta 3) exist, each a homodimer of a 112-amino-acid polypeptide derived from a larger precursor.
Purpose of the Study:
- To create dominant-negative mutants that inhibit TGF-beta secretion.
- To investigate the physiological roles of TGF-beta family members by blocking their secretion.
Main Methods:
- Introduction of specific mutations into the TGF-beta 1 precursor domain to inhibit secretion.
- Coexpression of these mutants with wild-type TGF-beta isoforms (1, 2, and 3).
Main Results:
- Mutated TGF-beta 1 precursors specifically and competitively inhibited the secretion of wild-type TGF-beta isoforms.
- These mutated versions function as dominant-negative mutants for TGF-beta secretion.
Conclusions:
- Overexpression of dominant-negative TGF-beta mutants effectively abolishes endogenous TGF-beta secretion in vitro and in vivo.
- This approach provides a valuable tool for elucidating the physiological functions of the TGF-beta superfamily.