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Alterations of the PPP2R1B gene in human lung and colon cancer
1McDermott Center for Human Growth and Development, The University of Texas Southwestern Medical Center, Dallas, Texas 75235, USA.
Abstract:
The PPP2R1B gene, which encodes the beta isoform of the A subunit of the serine/threonine protein phosphatase 2A (PP2A), was identified as a putative human tumor suppressor gene. Sequencing of the PPP2R1B gene, located on human chromosome 11q22-24, revealed somatic alterations in 15% (5 out of 33) of primary lung tumors, 6% (4 out of 70) of lung tumor-derived cell lines, and 15% (2 out of 13) of primary colon tumors. One deletion mutation generated a truncated PP2A-Abeta protein that was unable to bind to the catalytic subunit of the PP2A holoenzyme. The PP2R1B gene product may suppress tumor development through its role in cell cycle regulation and cellular growth control.
Insights
The PPP2R1B gene, a potential tumor suppressor, showed alterations in lung and colon tumors. Mutations can disrupt protein function, impacting cell growth and potentially suppressing tumor development.
Area of Science:
- Genetics
- Oncology
- Molecular Biology
Background:
- The serine/threonine protein phosphatase 2A (PP2A) holoenzyme plays a critical role in cellular regulation.
- The PPP2R1B gene encodes a subunit of PP2A, suggesting its involvement in cellular processes.
Purpose of the Study:
- To investigate the role of the PPP2R1B gene as a potential human tumor suppressor.
- To identify somatic alterations in the PPP2R1B gene in primary lung and colon tumors and cell lines.
Main Methods:
- Gene sequencing of PPP2R1B in primary lung tumors, lung tumor-derived cell lines, and primary colon tumors.
- Analysis of somatic alterations, including deletion mutations.
Main Results:
- Somatic alterations in PPP2R1B were found in 15% of primary lung tumors and 15% of primary colon tumors.
- Alterations were also detected in 6% of lung tumor-derived cell lines.
- A specific deletion mutation resulted in a truncated PP2A-Abeta protein lacking binding capacity to the PP2A catalytic subunit.
Conclusions:
- The PPP2R1B gene is a putative human tumor suppressor.
- Mutations in PPP2R1B may contribute to tumor development by affecting cell cycle regulation and growth control.
- The identified truncated protein suggests a mechanism for tumor suppression loss.