Breakpoint cluster region-Abelson tyrosine-protein kinase 1 fusion protein (BCR-ABL1)

The Breakpoint cluster region-Abelson tyrosine-protein kinase 1 (BCR-ABL1) fusion protein is a constitutively active non-receptor tyrosine kinase created by the reciprocal translocation between chromosomes 9 and 22, commonly referred to as the Philadelphia chromosome [Source: NIH/NCI]. This genetic rearrangement fuses the BCR gene with the ABL1 gene, resulting in a chimeric protein that bypasses normal regulatory mechanisms to drive uncontrolled cellular growth [Source: StatPearls]. BCR-ABL1 activates several key signaling cascades, including the PI3K/AKT, RAS/MAPK, and JAK/STAT pathways, which promote cell survival and inhibit apoptosis [Source: PubMed]. It is the hallmark molecular driver of Chronic Myeloid Leukemia (CML) and is also found in a significant percentage of adult Acute Lymphoblastic Leukemia (ALL) cases [Source: UniProt]. Pharmacological targeting of BCR-ABL1 with tyrosine kinase inhibitors (TKIs) like imatinib has transformed CML from a fatal disease into a manageable chronic condition [Source: PubMed]. However, the development of point mutations in the ABL1 kinase domain, most notably the T315I gatekeeper mutation, can lead to drug resistance, necessitating the use of later-generation or allosteric inhibitors like asciminib [Source: Nature Reviews Cancer].

Other names

BCR-ABLPhiladelphia chromosome proteinp210 BCR-ABLp190 BCR-ABLp230 BCR-ABLBCR-ABL1 chimeric protein

Inhibition of the constitutively active tyrosine kinase activity by competing with ATP for the binding site or through allosteric modulation of the myristoyl pocket, thereby blocking downstream oncogenic signaling pathways.