hnRNP K: one protein multiple processes

Bioessays. 2004 Jun;26(6):629-38. doi: 10.1002/bies.20048.


Since its original identification as a component of the heterogeneous nuclear ribonucleoprotein (hnRNP) complex, K protein has been found not only in the nucleus but also in the cytoplasm and mitochondria and is implicated in chromatin remodeling, transcription, splicing and translation processes. K protein contains multiple modules that, on one hand, bind kinases while, on the other hand, recruit chromatin, transcription, splicing and translation factors. Moreover, the K- protein-mediated interactions are regulated by signaling cascades. These observations are consistent with K protein acting as a docking platform to integrate signaling cascades by facilitating cross-talk between kinases and factors that mediate nucleic-acid-directed processes. Comparison of K across species reveals that it is an essential factor in metazoans, but not in yeast. Although some of the K protein interactions and functions are conserved in eukaryotes from yeast to man, the mammalian protein seems to play a wider role. The greater diversity of mammalian K protein interactions and function may reflect gain of novel docking sites and expansion evolutionary of gene expression networks.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.
  • Review

MeSH terms

  • Alternative Splicing
  • Animals
  • Chromatin / metabolism
  • Cytoplasm / metabolism
  • Gene Expression Regulation
  • Heterogeneous-Nuclear Ribonucleoprotein K / chemistry*
  • Heterogeneous-Nuclear Ribonucleoprotein K / physiology*
  • Humans
  • Mitochondria / metabolism
  • Models, Biological
  • Models, Genetic
  • Protein Biosynthesis
  • Protein Conformation
  • RNA / metabolism
  • RNA, Messenger / metabolism
  • Saccharomyces cerevisiae / metabolism
  • Signal Transduction
  • Transcription, Genetic


  • Chromatin
  • Heterogeneous-Nuclear Ribonucleoprotein K
  • RNA, Messenger
  • RNA