The heterogeneous nuclear ribonucleoprotein K (hnRNP K), is an RNA-binding protein containing 3 KH RNA-binding domains. It binds to both RNA and DNA and is a component of the hnRNP complex. hnRNP K is associated with pre-mRNA and appears to influence the processing of pre-mRNAs and metabolism of mRNA. hnRNP K is predominantly localized at the nucleus and shuttles between the nucleus and the cytoplasm. Therefore, hnRNP K is thought to be involved in the transport of mRNA. Phosphorylation of hnRNP K leads to its cytoplasmic accumulation and is important for cell migration and metastasis. In the cytoplasm, hnRNP K functions as a translational regulator of specific mRNAs such as c-myc mRNA, 16L2 mRNA, and r15-LOX mRNA. Further, it specifically associates with c-src kinase, leading to c-src activation and hnRNP K phosphorylation, which affect the binding of hnRNP K to RNA.