PRAC2 (prostate, rectum and colon expressed gene protein 2) encodes a small, 90-amino-acid arginine-rich protein of about 10.5 kDa from a locus on chromosome 17q21 that lies between HOXB13 and PRAC1; the same locus has also been catalogued as the antisense RNA HOXB13-AS1. The transcript is expressed mainly in prostate, rectum, distal colon and testis, with weaker expression in several other tissues and prostate cancer cell lines. The protein has no recognisable domains and has been reported to be nuclear. No molecular activity, binding partner or biological process has been demonstrated for it.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0005634 nucleus | EXP PMID:12746837 PRAC2: a new gene expressed in human prostate and prostate c... | ACCEPT | Summary: The discovery paper identified the PRAC2 protein by Western blot and reports it as a 10.5 kDa nuclear protein, matching the predicted mass of the 90-residue UniProt sequence. Reason: The only experimental localization for this protein, and consistent with its short, arginine-rich, domain-less sequence. The cached record is abstract-only and the abstract hedges ("seems to encode"), so the assay behind the nuclear call could not be inspected; the curator saw the full text and the annotation is accepted on that basis. Nucleus is the only established property of PRAC2. Supporting Evidence: PMID:12746837 The transcript seems to encode a 10.5-kDa nuclear protein. PMID:12746837 The PRAC2 transcript and protein were identified using Northern blot analysis, RACE-PCR, primer extension, and Western blots. |
| GO:0005634 nucleus | IEA GO_REF:0000044 | ACCEPT | Summary: Electronic mapping of the UniProt subcellular location "Nucleus", which is itself sourced from PMID:12746837. Reason: Correct mapping of an experimentally sourced UniProt location; it restates the EXP annotation and adds no independent evidence. Supporting Evidence: PMID:12746837 The transcript seems to encode a 10.5-kDa nuclear protein. |
Loading supporting content…
Download this section (compressed HTML)Q: Is endogenous PRAC2 protein detectable in prostate or colorectal epithelium, and does it remain nuclear at endogenous levels? The only localization comes from a single 2003 study, and the locus is also studied as a non-coding antisense RNA (HOXB13-AS1), so it is open whether the protein or the RNA carries the locus's reported effects.
Experiment: Raise antibodies or knock in an epitope tag at the endogenous PRAC2 ORF in a prostate cell line (e.g. LNCaP); confirm translation by immunoblot and targeted mass spectrometry; localize by immunofluorescence and fractionation; identify nuclear partners by proximity labelling; and compare start-codon mutation (protein-null, RNA-intact) with RNA knockdown to separate protein from RNA functions.
Hypothesis: PRAC2 protein is made endogenously and acts in the nucleus independently of the HOXB13-AS1 RNA function.
Type: protein detection, localization and separation-of-function
Loading supporting content…
Download this section (compressed HTML)Loading supporting content…
Download this section (compressed HTML)