SF3B1

This gene encodes subunit 1 of the splicing factor 3b protein complex. Splicing factor 3b, together with splicing factor 3a and a 12S RNA unit, forms the U2 small nuclear ribonucleoproteins complex (U2 snRNP). The splicing factor 3b/3a complex binds pre-mRNA upstream of the intron's branch site in a sequence independent manner and may anchor the U2 snRNP to the pre-mRNA. Splicing factor 3b is also a component of the minor U12-type spliceosome. The carboxy-terminal two-thirds of subunit 1 have 22 non-identical, tandem HEAT repeats that form rod-like, helical structures. Alternative splicing results in multiple transcript variants encoding different isoforms. [provided by RefSeq, Jul 2008]

Splicing Factor 3b Subunit 1

Involved in pre-mRNA splicing as a component of the splicing factor SF3B complex (PubMed:27720643).
SF3B complex is required for 'A' complex assembly formed by the stable binding of U2 snRNP to the branchpoint sequence (BPS) in pre-mRNA. Sequence independent binding of SF3A/SF3B complex upstream of the branch site is essential, it may anchor U2 snRNP to the pre-mRNA (PubMed:12234937).
Together with other U2 snRNP complex components may also play a role in the selective processing of microRNAs (miRNAs) from the long primary miRNA transcript, pri-miR-17-92 (By similarity).
May also be involved in the assembly of the 'E' complex (PubMed:10882114).
Belongs also to the minor U12-dependent spliceosome, which is involved in the splicing of rare class of nuclear pre-mRNA intron (PubMed:15146077).

Chromatin remodeling1 PublicationIC:ComplexPortal
mRNA splicing, via spliceosomeManual Assertion Based On ExperimentIDA:UniProtKB
Positive regulation of histone acetylation1 PublicationIC:ComplexPortal
Positive regulation of transcription by RNA polymerase I1 PublicationIC:ComplexPortal
Positive regulation of transcription by RNA polymerase II1 PublicationIC:ComplexPortal
Positive regulation of transcription by RNA polymerase IIIManual Assertion Based On ExperimentIDA:ComplexPortal
RNA splicing1 PublicationIC:UniProtKB
RNA splicing, via transesterification reactions1 PublicationNAS:UniProtKB
Spliceosomal complex assemblyManual Assertion Based On ExperimentIBA:GO_Central

Nucleus
Nucleus speckle
During mitosis, transiently dispersed from the nuclear speckles to the cytoplasm.

Phosphorylated. Phosphorylation occurs concomitantly with the splicing catalytic steps. Phosphorylation on Thr-244, Thr-248 and Thr-313 by cyclin-dependent kinases promotes interaction with PPP1R8 during mitosis.
Citrullinated by PADI4.