Nucleolin is a ubiquitous, nonhistone nucleolar phosphoprotein of eukaryotic cells and is present in abundance in the dense fibrillar and granular regions of the nucleolus. It is also able to localize in the nucleus, in the cytoplasm, and at the cell surface. Nucleolin is a multifunctional RNA-binding protein involved in many cellular processes, including ribosome biogenesis, the processing of ribosomal RNA (rRNA), mRNA stability, transcriptional regulation, and cell proliferation; it is also a downstream target of several signal transduction pathways.
Regulation of Nucleolin Function as a Phosphoprotein
The multiple activities of nucleolin are regulated by covalent modifications, most notably phosphorylation, methylation, proteolysis, and ADP-ribosylation. Via phosphorylation, nucleolin function is coupled to growth control. Active rRNA transcription is positively correlated with highly phosphorylated nucleolin. In growing cells, casein kinase II (CKII)...
KeywordsCervical Cancer Ribosome Biogenesis Cervix Uterus Cdc2 Kinase rDNA Transcription
- Masumi A, Fukazawa H, Shimazu T et al (2006) Nucleolin is involved in interferon regulatory factor-2-dependent transcriptional activation. Oncongene 25:5113–5124Google Scholar