Heterogeneous nuclear ribonucleoprotein K (also protein K) is a protein that in humans is encoded by the HNRNPKgene.[5] It is found in the cell nucleus that binds to pre-messenger RNA (mRNA) as a component of heterogeneous ribonucleoprotein particles. The simianhomolog is known as protein H16. Both proteins bind to single-stranded DNA as well as to RNA and can stimulate the activity of RNA polymerase II, the protein responsible for most gene transcription. The relative affinities of the proteins for DNA and RNA vary with solution conditions and are inversely correlated, so that conditions promoting strong DNA binding result in weak RNA binding.[6]
RNA binding protein domains in other proteins that are similar to the RNA binding domain of protein K are called K-homology or KH domains.
^"Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
^"Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
^Dejgaard K, Leffers H, Rasmussen HH, Madsen P, Kruse TA, Gesser B, et al. (February 1994). "Identification, molecular cloning, expression and chromosome mapping of a family of transformation upregulated hnRNP-K proteins derived by alternative splicing". Journal of Molecular Biology. 236 (1): 33–48. doi:10.1006/jmbi.1994.1116. PMID8107114.