Nucleolin: a multiFACeTed protein.

Nucleolin is an abundant, ubiquitously expressed protein that is found in various cell compartments, especially in the nucleolus, of which it is a major component. This multifunctional protein has been described as being a part of many pathways, from interactions with viruses at the cellular membrane to essential processing of the ribosomal RNA in the nucleolus. However, most of the molecular details of these different functions are not understood. Here, we focus on the role of nucleolin in transcription, especially some recent findings describing the protein as a histone chaperone [with functional similarity to the facilitates chromatin transcription (FACT) complex] and a chromatin co-remodeler. These new properties could help reconcile discrepancies in the literature regarding the role of nucleolin in transcription.