Seroatlas · Human Serome Atlas

SF3A3

Splicing factor 3A subunit 3

Also known as: PRP9, PRPF9, SAP61, SF3A3_HUMAN, SF3a60

Cross-references: UniProt · Ensembl · Human Protein Atlas · GeneCards · NCBI Gene

Protein identityUniProt · HPA

UniProt accession: Q12874
Gene: SF3A3
Ensembl: ENSG00000183431
Chromosome: 1
Canonical length: 501 aa
Protein class: Plasma proteins, Predicted intracellular proteins
Subcellular location: Nucleoplasm,Nuclear speckles

OverviewNCBI Gene

This gene encodes subunit 3 of the splicing factor 3a protein complex. The splicing factor 3a heterotrimer includes subunits 1, 2 and 3 and is necessary for the in vitro conversion of 15S U2 snRNP into an active 17S particle that performs pre-mRNA splicing. Subunit 3 interacts with subunit 1 through its amino-terminus while the zinc finger domain of subunit 3 plays a role in its binding to the 15S U2 snRNP. This gene has a pseudogene on chromosome 20. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Mar 2016]

Canonical amino-acid sequenceUniProt

501 residues, UniProt reviewed canonical sequence.

>Q12874|SF3A3
     1  METILEQQRR YHEEKERLMD VMAKEMLTKK STLRDQINSD HRTRAMQDRY MEVSGNLRDL
    61  YDDKDGLRKE ELNAISGPNE FAEFYNRLKQ IKEFHRKHPN EICVPMSVEF EELLKARENP
   121  SEEAQNLVEF TDEEGYGRYL DLHDCYLKYI NLKASEKLDY ITYLSIFDQL FDIPKERKNA
   181  EYKRYLEMLL EYLQDYTDRV KPLQDQNELF GKIQAEFEKK WENGTFPGWP KETSSALTHA
   241  GAHLDLSAFS SWEELASLGL DRLKSALLAL GLKCGGTLEE RAQRLFSTKG KSLESLDTSL
   301  FAKNPKSKGT KRDTERNKDI AFLEAQIYEY VEILGEQRHL THENVQRKQA RTGEEREEEE
   361  EEQISESESE DEENEIIYNP KNLPLGWDGK PIPYWLYKLH GLNINYNCEI CGNYTYRGPK
   421  AFQRHFAEWR HAHGMRCLGI PNTAHFANVT QIEDAVSLWA KLKLQKASER WQPDTEEEYE
   481  DSSGNVVNKK TYEDLKRQGL L

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against SF3A3 can act on the native protein depends on physical access: surface and secreted proteins are reachable by circulating antibodies, intracellular proteins usually are not.

Antibody reachability: Intracellular
Secreted: No
Transmembrane segments: 0
Mean surface accessibility (rSASA): 0.35
Highest tissue expression: 55 nTPM

Expression across tissuesHPA

Tissue

bone marrow: 55 nTPM
skeletal muscle: 52 nTPM
tonsil: 42 nTPM
thymus: 40 nTPM
lymph node: 37 nTPM
ovary: 34 nTPM

Single-cell type

oocytes: 332 nCPM
late primary spermatocytes: 129 nCPM
erythrocyte progenitors: 108 nCPM
early primary spermatocytes: 100 nCPM
myonuclei: 92 nCPM
extravillous trophoblasts: 86 nCPM

Immune cell

T-reg: 76 nTPM
naive CD4 T-cell: 70 nTPM
naive B-cell: 69 nTPM
memory CD4 T-cell: 65 nTPM
non-classical monocyte: 62 nTPM
total PBMC: 62 nTPM

Brain region

cerebellum: 25 nTPM
white matter: 25 nTPM
thalamus: 24 nTPM
choroid plexus: 24 nTPM
midbrain: 23 nTPM
hypothalamus: 23 nTPM

Genetic constraint and essentialitygnomAD · DepMap

Does the body need this protein intact? Low LOEUF or a strong DepMap dependency means loss or blockade of the protein is likely to be felt.

gnomAD LOEUF (loss-of-function intolerance): 0.12
gnomAD pLI: 1
gnomAD missense Z: 3.62
DepMap mean gene effect: -2.34
DepMap dependency class: pan

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 7% of surveyed tumor types (aggregate summary; per-cohort expression, alteration, and survival load in the interactive view).

OntologyGO

Biological processes

Molecular functions

Cellular components

Protein domainsUniProt · Pfam · InterPro

Matrin/U1-C, C2H2-type zinc finger
SDE2/SF3A3, SAP domain
RNA Processing and DNA Damage Response Regulator
Replication stress response SDE2 C-terminal
Splicing factor SF3a60 binding domain
Splicing factor SF3a60 /Prp9 subunit, C-terminal
SF3A3 domain
SF3a60/Prp9 C-terminal
Splicing factor SF3a60 binding domain
Pre-mRNA-splicing factor SF3A3, of SF3a complex, Prp9

KeywordsUniProt

InteractionsUniProt · HPA

Protein binding partners of SF3A3 in the human serome: UniProt-annotated complex subunits plus reported interactors. Each links to its own Seroatlas record.

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads SF3A3 as an antibody target. Whether an autoantibody or antibody against SF3A3 could matter depends on whether native SF3A3 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

SF3A3 is annotated as predominantly intracellular. Intracellular proteins are common autoantibody markers, becoming visible to the immune system after cell injury or altered processing, but are usually markers of disease rather than direct drivers.

Annotation status

The present source text does not explicitly label SF3A3 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Loading the interactive Seroatlas protein explorer...