Question
The BCR-ABL1 oncoprotein exhibits constitutive activity of which one of the following enzymes?
The correct answer is
Tyrosine kinase
BCR-ABL1 Oncoprotein Enzyme Activity
The BCR-ABL1 oncoprotein is an abnormal fusion protein resulting from a specific chromosomal translocation (the Philadelphia chromosome). This protein is a hallmark of certain cancers, particularly Chronic Myeloid Leukemia (CML).
Constitutive Kinase Function
The defining characteristic of the BCR-ABL1 oncoprotein is its constitutive activity. This means the enzyme is permanently switched 'on', unlike its normal counterparts which require specific signals to activate.
Specifically, the BCR-ABL1 protein possesses abnormally high tyrosine kinase activity.
Mechanism of Action
- Tyrosine kinases are enzymes that add phosphate groups to tyrosine residues on substrate proteins.
- In the case of BCR-ABL1, this uncontrolled tyrosine phosphorylation leads to the activation of multiple downstream signaling pathways.
- These pathways promote cell proliferation, survival, and resistance to apoptosis, driving leukemogenesis.
Conclusion
Therefore, the BCR-ABL1 oncoprotein exhibits constitutive activity of a Tyrosine kinase.
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Important Questions from Leukemia
- The Rai staging system and Binet staging system are the two widely used staging systems used for staging which of the following hematological malignancies?
- Imatinib, Dasatinib, Nilotinib and Ponatinib are examples of which class of drugs?
- Which one of the following is a clonal haematopoietic stem cell disorder in which phenotypically normal red blood cells, granulocytes and platelets accumulate in the absence of a recognizable physiological stimulus?
- Which one of the following combinations of drugs can be used for treatment of relapsed myeloma ?
- Which one of the following is NOT true regarding Chronic Myeloid Leukaemia (CML)?
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