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The human p167 gene encodes a unique structural protein that contains centrosomin A homology and associates with a
1Bristol-Myers Squibb Pharmaceutical Research Institute, Seattle, WA 98121, USA.
Abstract:
The characterization of novel cytoplasmic, structural, and enzymatic proteins has been enhanced by a panel of monoclonal antibodies specific for protein substrates of transforming and nontransforming c-Src mutants. These protein substrates have included the focal adhesion kinase (FAK), cortactin, AFAP-110, p120CAS, and p130CAS. The monoclonal antibody 4G8 was generated as part of this panel of antibodies and was used to isolate the human gene for a 167-kD polypeptide. The cDNA sequence is 5,238 nucleotides in length with a predicted open reading frame consisting of 1,382 amino acids. The polypeptide is largely hydrophilic and highly charged. The central region of p167 has 88% identity with the entire 278-amino-acid encoded sequence of the murine centrosomin A gene. The carboxyl third of p167 contains a unique cluster of 10 amino acid repeats with the consensus sequence (A/M)DDDRGPRRG. The p167 protein was found primarily in the cytoplasm of lymphocytes and is part of a multicomponent protein complex with prominent members of 167, 120, 64, 45, 40, 38, and 25 kD. Finally, we illustrate the conservation of p167 and its associated complex, and demonstrate its expression in different human tissues and cell types. The data suggest that p167 is novel and has an important cellular function as a cytoplasmic structural protein.
Insights
Researchers identified a novel cytoplasmic structural protein, p167, using monoclonal antibodies. This protein, found in lymphocytes, is conserved across species and plays a key cellular role.
Area of Science:
- Cell Biology
- Molecular Biology
- Protein Biochemistry
Background:
- Monoclonal antibodies enhance characterization of novel proteins.
- c-Src mutants target specific protein substrates like FAK, cortactin, and CAS proteins.
Purpose of the Study:
- To characterize a novel 167-kD polypeptide (p167) identified using monoclonal antibody 4G8.
- To investigate the cellular localization, structure, and function of p167.
Main Methods:
- Generation of monoclonal antibodies against c-Src substrates.
- Isolation and sequencing of the human p167 gene.
- Bioinformatic analysis of the p167 cDNA and protein sequence.
- Biochemical analysis of the p167 protein complex and its expression.
Main Results:
- The human p167 gene encodes a 1,382-amino acid polypeptide with unique structural features.
- p167 shows high homology to murine centrosomin A and contains a novel repeat sequence.
- p167 is a cytoplasmic protein in lymphocytes, part of a large multi-protein complex.
- p167 and its complex are conserved and expressed across various human tissues and cell types.
Conclusions:
- p167 is a novel cytoplasmic structural protein with a conserved cellular function.
- The characterization of p167 provides insights into protein complexes involved in cellular structure.