Splicing factor 3B subunit 4 (SF3B4)

Splicing factor 3B subunit 4 (SF3B4) is an RNA-binding protein component of the SF3B complex, which is essential for pre-mRNA splicing as part of the spliceosome—specifically, the U2 small nuclear ribonucleoprotein (snRNP) complex[3][7]. SF3B4 recognizes and cross-links to regions of pre-mRNA immediately upstream of branchpoint sequences and facilitates the stable binding of the U2 snRNP to the branchpoint, being involved in the assembly of early spliceosomal complexes (A, E, B, and C)[3][7]. SF3B4 directly binds pre-mRNA and participates in both the major (U2-type) and minor (U12-type) spliceosomes[3]. Dysregulation or mutation (notably haploinsufficiency) in SF3B4 causes Nager syndrome, a congenital disorder with craniofacial and limb defects[1][3][6][7]. SF3B4 has also been implicated in oncogenic processes—its upregulation promotes tumor cell proliferation, migration, and invasion in several cancers including clear cell renal cell carcinoma and cervical cancer, possibly through alternative splicing and translational control mechanisms[2][5]. Recent data suggest additional roles for SF3B4 in mRNA transport, translation regulation at the endoplasmic reticulum, and cell signaling[1][2][5]. No approved drugs or direct pharmacological inhibitors targeting SF3B4 are currently noted.

Other names

SAP49SF3b49Hsh49AFD1Spliceosome-associated protein 49Pre-mRNA-splicing factor SF3b 49 kDa subunit