PRP45/YAL032C Summary Help

Standard Name PRP45 1
Systematic Name YAL032C
Alias FUN20 2
Feature Type ORF, Verified
Description Protein required for pre-mRNA splicing; associates with the spliceosome and interacts with splicing factors Prp22p and Prp46p; orthologous to human transcriptional coactivator SKIP and can activate transcription of a reporter gene (1, 3, 4 and see Summary Paragraph)
Name Description Pre-mRNA Processing 1
Chromosomal Location
ChrI:84474 to 83335 | ORF Map | GBrowse
Note: this feature is encoded on the Crick strand.
Gene Ontology Annotations All PRP45 GO evidence and references
  View Computational GO annotations for PRP45
Molecular Function
Manually curated
Biological Process
Manually curated
Cellular Component
Manually curated
Regulators 3 genes
Classical genetics
Large-scale survey
reduction of function
154 total interaction(s) for 85 unique genes/features.
Physical Interactions
  • Affinity Capture-MS: 80
  • Affinity Capture-RNA: 1
  • Affinity Capture-Western: 1
  • Co-purification: 1
  • Reconstituted Complex: 2
  • Two-hybrid: 55

Genetic Interactions
  • Dosage Lethality: 1
  • Dosage Rescue: 1
  • Negative Genetic: 1
  • Synthetic Growth Defect: 2
  • Synthetic Lethality: 9

Expression Summary
Length (a.a.) 379
Molecular Weight (Da) 42,482
Isoelectric Point (pI) 9.93
Phosphorylation PhosphoGRID | PhosphoPep Database
sequence information
ChrI:84474 to 83335 | ORF Map | GBrowse
Note: this feature is encoded on the Crick strand.
Last Update Coordinates: 2011-02-03 | Sequence: 1996-07-31
Subfeature details
Most Recent Updates
Coordinates Sequence
CDS 1..1140 84474..83335 2011-02-03 1996-07-31
Retrieve sequences
Analyze Sequence
S288C only
S288C vs. other species
S288C vs. other strains
External Links All Associated Seq | Entrez Gene | Entrez RefSeq Protein | MIPS | Search all NCBI (Entrez) | UniProtKB
Primary SGDIDS000000030

Prp45p is a spliceosomal protein that plays a role in the second step of splicing. While its deletion does not affect splicing of introns that match the canonical splice site consensus sequences, it is needed for the splicing of introns with non-canonical 5', branch point, or 3' splice consensus sites (5). It is found in association with several members of the Prp19-associated NineTeen Complex (NTC) (6, 7, 5). Prp45p, like NineTeen Complex members, is also found in forms of the spliceosome containing the U2, U5, and U6 snRNPs, which are the catalytic forms of the spliceosome (1, 6, 8). Strains deleted for PRP45 are inviable (2) and depletion of Prp45p results in accumulation of unspliced precursor RNAs (1). A temperature sensitive allele of prp45 is synthetically lethal with alleles of several second step splicing factors (SLU7, PRP17, PRP18, and PRP22) and with several NTC components (SYF1, CLF1, NTC20, and CEF1; 5). Prp45p undergoes sumoylation and is a substrate of the SUMO E3 ligase Siz1p (9, 10).

PRP45 is an ortholog of the human SKIP protein which is highly conserved across eukaryotes and which is essential in C. elegans and S. pombe, as well as in S. cerevisiae. In humans, SKIP is characterized as a transcriptional coactivator acting on several signaling pathways, but more recently it has also been shown to colocalize with spliceosomes and can complement a prp45 null mutation in S. cerevisiae, suggesting that it plays a dual role (4 and refs therein). However, while Prp45p can activate expression of a reporter gene when fused to a DNA-binding domain (3), it is considered to be solely a splicing protein in S. cerevisiae (5). The fact that the sequence of Prp45p from S. cerevisiae is shorter and more diverged from the consensus than those of its orthologs, completely lacking a conserved proline-rich domain present in other species, may explain this difference in the function between S. cerevisiae Prp45p and the human SKIP protein (4, 11).

Last updated: 2009-12-01 Contact SGD

References cited on this page View Complete Literature Guide for PRP45
1) Albers M, et al.  (2003) Identification and characterization of Prp45p and Prp46p, essential pre-mRNA splicing factors. RNA 9(1):138-50
2) Diehl BE and Pringle JR  (1991) Molecular analysis of Saccharomyces cerevisiae chromosome I: identification of additional transcribed regions and demonstration that some encode essential functions. Genetics 127(2):287-98
3) Martinkova K, et al.  (2002) Functional mapping of Saccharomyces cerevisiae Prp45 identifies the SNW domain as essential for viability. J Biochem 132(4):557-63
4) Figueroa JD and Hayman MJ  (2004) The human Ski-interacting protein functionally substitutes for the yeast PRP45 gene. Biochem Biophys Res Commun 319(4):1105-9
5) Gahura O, et al.  (2009) Prp45 affects Prp22 partition in spliceosomal complexes and splicing efficiency of non-consensus substrates. J Cell Biochem 106(1):139-51
6) Ohi MD, et al.  (2002) Proteomics analysis reveals stable multiprotein complexes in both fission and budding yeasts containing Myb-related Cdc5p/Cef1p, novel pre-mRNA splicing factors, and snRNAs. Mol Cell Biol 22(7):2011-24
7) Wang Q, et al.  (2003) The Clf1p splicing factor promotes spliceosome assembly through N-terminal tetratricopeptide repeat contacts. J Biol Chem 278(10):7875-83
8) Tardiff DF and Rosbash M  (2006) Arrested yeast splicing complexes indicate stepwise snRNP recruitment during in vivo spliceosome assembly. RNA 12(6):968-79
9) Wohlschlegel JA, et al.  (2004) Global analysis of protein sumoylation in Saccharomyces cerevisiae. J Biol Chem 279(44):45662-8
10) Reindle A, et al.  (2006) Multiple domains in Siz SUMO ligases contribute to substrate selectivity. J Cell Sci 119(Pt 22):4749-57
11) Ambrozkova M, et al.  (2001) The fission yeast ortholog of the coregulator SKIP interacts with the small subunit of U2AF. Biochem Biophys Res Commun 284(5):1148-54