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Aliases KPNA3, IPOA4, SRP1, SRP1gamma, SRP4, hSRP1, karyopherin subunit alpha 3
External IDs MGI: 1100863 HomoloGene: 20520 GeneCards: KPNA3
Genetically Related Diseases
RNA expression pattern
PBB GE KPNA3 221503 s at fs.png

PBB GE KPNA3 221502 at fs.png
More reference expression data
Species Human Mouse
RefSeq (mRNA)



RefSeq (protein)



Location (UCSC) Chr 13: 49.7 – 49.79 Mb Chr 14: 61.37 – 61.44 Mb
PubMed search [2] [3]
View/Edit Human View/Edit Mouse

Importin subunit alpha-3 is a protein that in humans is encoded by the KPNA3 gene.[4][5]

The transport of molecules between the nucleus and the cytoplasm in eukaryotic cells is mediated by the nuclear pore complex (NPC) which consists of 60–100 proteins and is probably 120 million daltons in molecular size. Small molecules (up to 70 kD) can pass through the nuclear pore by nonselective diffusion; larger molecules are transported by an active process. Most nuclear proteins contain short basic amino acid sequences known as nuclear localization signals (NLSs). KPNA3, encodes a protein similar to certain nuclear transport proteins of Xenopus and human. The predicted amino acid sequence shows similarity to Xenopus importin, yeast SRP1, and human RCH1 (KPNA2), respectively. The similarities among these proteins suggests that karyopherin alpha-3 may be involved in the nuclear transport system.[6]


KPNA3 has been shown to interact with KPNB1.[5][7]


  1. ^ "Diseases that are genetically associated with KPNA3 view/edit references on wikidata". 
  2. ^ "Human PubMed Reference:". 
  3. ^ "Mouse PubMed Reference:". 
  4. ^ Takeda S, Fujiwara T, Shimizu F, Kawai A, Shinomiya K, Okuno S, Ozaki K, Katagiri T, Shimada Y, Nagata M, Watanabe T, Takaichi A, Kuga Y, Suzuki M, Hishigaki H, Takahashi E, Shin S, Nakamura Y, Hirai Y (Jun 1997). "Isolation and mapping of karyopherin alpha 3 (KPNA3), a human gene that is highly homologous to genes encoding Xenopus importin, yeast SRP1 and human RCH1". Cytogenet Cell Genet. 76 (1–2): 87–93. doi:10.1159/000134521. PMID 9154134. 
  5. ^ a b Nachury MV, Ryder UW, Lamond AI, Weis K (Feb 1998). "Cloning and characterization of hSRP1 gamma, a tissue-specific nuclear transport factor". Proc Natl Acad Sci U S A. 95 (2): 582–7. doi:10.1073/pnas.95.2.582. PMC 18463Freely accessible. PMID 9435235. 
  6. ^ "Entrez Gene: KPNA3 karyopherin alpha 3 (importin alpha 4)". 
  7. ^ Köhler, M; Speck C; Christiansen M; Bischoff F R; Prehn S; Haller H; Görlich D; Hartmann E (Nov 1999). "Evidence for distinct substrate specificities of importin alpha family members in nuclear protein import". Mol. Cell. Biol. UNITED STATES. 19 (11): 7782–91. doi:10.1128/mcb.19.11.7782. ISSN 0270-7306. PMC 84838Freely accessible. PMID 10523667. 

Further reading[edit]