Nuclear shift of hnRNP K protein in neoplasms and other states of enhanced cell proliferation.
The heterogeneous nuclear ribonucleoprotein K (hnRNP K), is a ubiquitously expressed protein that interacts with signal transducers, proteins that modulate gene expression and selective RNA and DNA motifs. K protein is modified in response to extracellular signals and directly regulates rates of transcription and translation. We used serum-treated hepatocyte culture, liver after partial hepatectomy and hepatic neoplasms as systems to compare expression, subcellular distribution and tyrosine phosphorylation of K protein in quiescent and dividing cells. The results show that expression of K protein mRNA was increased in states of enhanced proliferation. Levels of nuclear K protein were also higher in proliferating compared to resting cells. In contrast, levels of cytoplasmic K protein were the same or lower in dividing compared to quiescent cells. States of enhanced proliferation were also associated with increased levels of K protein tyrosine phosphorylation. Nuclear shift of K protein in dividing cells may reflect involvement of K protein in signalling multiple events that regulate expression of genes in proliferating cells.
Ostrowski
J
J
Department of Gastroenterology, Medical Center for Postgraduate Education, Maria Sklodowska-Curie Memorial Cancer Center, ul. Roentgena 5, 02-781 Warsaw, Poland. jostrow@warman.com.pl
Bomsztyk
K
K
D018929:Cell Culture Techniques; D002455:Cell Division; D002467:Cell Nucleus / Q000737:chemistry; D003593:Cytoplasm / Q000737:chemistry; D005786:Gene Expression Regulation; D006498:Hepatectomy; D022781:Hepatocytes; D034641:Heterogeneous-Nuclear Ribonucleoprotein K / Q000096:biosynthesis* / Q000378:metabolism / Q000493:pharmacokinetics; D006801:Humans; D008113:Liver Neoplasms / Q000473:pathology*; D008115:Liver Regeneration; D010766:Phosphorylation; D015398:Signal Transduction; D014443:Tyrosine / Q000378:metabolism
D034641:Heterogeneous-Nuclear Ribonucleoprotein K; D014443:Tyrosine