Pre-mRNA 3'-end-processing factor FIP1-like 1 (FIP1L1)

Pre-mRNA 3'-end-processing factor FIP1-like 1 (FIP1L1) is a protein-coding subunit of the cleavage and polyadenylation specificity factor (CPSF) complex, essential for polyadenylation and processing of mRNA 3'-ends in eukaryotic cells. FIP1L1 recognizes polyadenylation sites and binds U-rich RNA sequences, stimulating poly(A) polymerase activity to stabilize mRNAs for export and translation. In humans, a chromosomal deletion at 4q12 can create a fusion gene (FIP1L1-PDGFRA), resulting in a constitutively active tyrosine kinase driving hypereosinophilic syndrome and chronic eosinophilic leukemia. Imatinib and other kinase inhibitors target the fusion protein in affected patients. FIP1L1 is frequently studied for its role in RNA processing, leukemogenesis via gene fusion, and as a diagnostic, therapeutic, and prognostic marker in selected hematological malignancies.

Other names

FIP1-like 1 proteinFIP1_HUMANFIP1hFip1RHEFactor interacting with PAPRearranged in hypereosinophilia

Tyrosine kinase inhibition: Drugs like imatinib inhibit the constitutively active tyrosine kinase activity of the FIP1L1-PDGFRA fusion protein, leading to reduced proliferation of leukemia cells.