PRAC2 notes

2026-10-08 — initial review (MICROPROTEINS Tier 2)

UniProt D3DTV9 (PRAC2_HUMAN), PE2, 90 aa, sequence version 1 since 2010; no domains,
no predicted TM; N-terminal Arg-rich segment (MDRRRMALRPGSRRP). HGNC (REST, 2026-10-08):
locus_type "gene with protein product", name "PRAC2 small nuclear protein"; previous
symbols C17orf93, NCRNA00253, HOXB13-AS1, HOXB-AS5. Located at 17q21 between HOXB13 and
PRAC1.

Literature

• Only one paper addresses the protein: Olsson et al. 2003 PMID:12746837, abstract-only
  in cache. "The PRAC2 transcript and protein were identified using Northern blot
  analysis, RACE-PCR, primer extension, and Western blots." and "The transcript seems to
  encode a 10.5-kDa nuclear protein." The predicted mass of the 90-aa UniProt sequence
  (10,428 Da) matches 10.5 kDa. The full text (Wiley, not in PMC) was not available, so the
  assay behind "nuclear" (likely tagged over-expression) could not be checked.
• Expression: prostate, rectum, distal colon, testis PMID:12746837; HPA "Group enriched
  (intestine, prostate)" (UniProt DR line).
• Other PubMed hits for PRAC2 are DNA-methylation biomarker studies of the locus; the
  HOXB13-AS1 hits (PMID:30105866 glioma; PMID:31558162 LUAD methylation) treat the
  transcript as a lncRNA acting on HOXB13 methylation via EZH2. None concern the protein,
  so they are not cited in the review.
• No molecular function, partner or process reported for the protein.

Actions

• EXP nucleus PMID:12746837: ACCEPT (defer to curator; consistent with abstract; full
  text not seen).
• IEA nucleus (SubCell): ACCEPT (same claim, derived from the same paper).
• No NEW terms: nothing beyond localization is supported.