| Among them , hnRNP A , D , E , 1 , and K are known to shuttle between the nucleus and the cytoplasm . hnRNP E 2 has been seen to stabilize alpha globin mRNA and to enhance polioviral mRNA translation . hnRNP K modulates transcription and translation of some mRNAs . hnRNP 1 and its homologue hnRNP L have been suggested to enhance translation of some IRES dependent mRNAs . ^^^ In the case of hnRNP E 2 and hnRNP K , the N terminal half of the proteins containing two KH ( K homologous ) domains were required for protein protein interaction , and the second quarter of hnRNP 1 and hnRNP L containing RRM 2 ( RNA recognition motif 2 ) was essential for protein protein interaction . hnRNP A 1 and C 1 did not form complexes with other hnRNPs in our assay systems . ^^^ |