High impact information on PRPF4

• USA-CyP forms separate, stable complexes with hPrp18 and hPrp4 in which the active site of the cyclophilin is exposed [1].
• PRP4K is implicated in pre-mRNA splicing as the homologue of the Schizosaccharomyces pombe pre-mRNA splicing kinase Prp4p, and it is enriched in SC35-containing nuclear splicing speckles [2].
• The primary amino acid sequence homology between human Hprp4p and yeast Prp4p led to the discovery of two additional WD repeats in yeast Prp4p [3].
• These findings suggest that the NH(2)-terminal region of hPRP4 may play regulatory roles under an unidentified signal transduction pathway through Clk1 [4].
• Prp4 is a protein kinase of Schizosaccharomyces pombe identified through its role in pre-mRNA splicing, and belongs to a kinase family including mammalian serine/arginine-rich protein-specific kinases and Clks, whose substrates are serine/arginine-rich proteins [4].

Biological context of PRPF4

• Mapping of the human HPRP3 and HPRP4 genes encoding U4/U6-associated splicing factors to chromosomes 1q21.1 and 9q31-q33 [5].
• A mutational analysis of prp4 revealed that the protein consists of a short N-terminal domain, containing several essential motifs, which is followed by the kinase catalytic domain comprising the C-terminus of the protein [6].
• Overexpression of N-terminal mutations disturbs mitosis and produces elongated cells, Using a PCR approach, we isolated a putative homologue of Prp4 from human and mouse cells [6].

Anatomical context of PRPF4

• Our results lead to a model in which USA-CyP is carried into the spliceosome in complexes with hPrp4 and hPrp18, and USA-CyP acts during splicing within these complexes [1].

Associations of PRPF4 with chemical compounds

• Amino acid analysis of intact PRP-6 and sequence determination of PRP-6 chymotryptic peptides, residues 15-24 and 26-35, show a single difference in PRP-6, compared to the most similar, characterized PRP, PRP-4, in that residue 30 is histidine in PRP-6, rather than arginine as in PRP-4 and in all the other sequenced PRPs [7].

Other interactions of PRPF4

• A database homology search revealed a significant degree of overall homology (57.8% similarity, 33.9% identity) between the human 60kD protein and the Saccharomyces cerevisiae U4/U6 snRNP protein Prp4p [8].
• A faster adsorption process is observed for PRP-3, PRP-4, PIF-f, and statherin [9].

Analytical, diagnostic and therapeutic context of PRPF4

• Northern blot analysis revealed that hPRP4 mRNA was ubiquitously expressed in multiple tissues [4].
• Indirect immunofluorescence analysis revealed that endogenous hPRP4 was distributed in a nuclear speckled pattern and colocalized with SF2/ASF in HeLa S3 cells [4].

References