Adaptor proteins in long noncoding RNA biology.

Long noncoding RNAs (lncRNAs) are a heterogeneous class of noncoding RNAs that have gained increasing attention due to their vital roles in the regulation of diverse cellular processes. Because lncRNAs are generally expressed at low levels, are poorly conserved, and can act via diverse mechanisms, investigating the molecular mechanisms by which lncRNAs act is challenging. Similar to mRNAs, lncRNAs bind to RNA-binding proteins (RBPs) and in some cases, have been shown to regulate the activity of the RBP they bind to. Furthermore, recent studies have shown that some lncRNAs directly bind to a specific RBP that, in turn, forms a complex with other proteins that mediate the effects of the lncRNA. We termed such RBPs as adaptor proteins because they function as adaptors to recruit other proteins that indirectly associate with the lncRNA. Here, we discuss the emerging roles of adaptor proteins in lncRNA function and propose mechanistic scenarios and strategies to identify adaptor proteins that could play vital roles in the biology of a lncRNA. This article is part of a Special Issue entitled: ncRNA in control of gene expression edited by Kotb Abdelmohsen.