RNA recognition motif 3 (RRM3) found in vertebrate heterogeneous nuclear ribonucleoprotein Q (hnRNP Q)
This subgroup corresponds to the RRM3 of hnRNP Q, also termed glycine- and tyrosine-rich RNA-binding protein (GRY-RBP), or NS1-associated protein 1 (NASP1), or synaptotagmin-binding, cytoplasmic RNA-interacting protein (SYNCRIP). It is a ubiquitously expressed nuclear RNA-binding protein identified as a component of the spliceosome complex, as well as a component of the apobec-1 editosome. As an alternatively spliced version of NSAP, it acts as an interaction partner of a multifunctional protein required for viral replication, and is implicated in the regulation of specific mRNA transport. hnRNP Q has also been identified as SYNCRIP that is a dual functional protein participating in both viral RNA replication and translation. As a synaptotagmin-binding protein, hnRNP Q plays a putative role in organelle-based mRNA transport along the cytoskeleton. Moreover, hnRNP Q has been found in protein complexes involved in translationally coupled mRNA turnover and mRNA splicing. It functions as a wild-type survival motor neuron (SMN)-binding protein that may participate in pre-mRNA splicing and modulate mRNA transport along microtubuli. hnRNP Q contains an acidic auxiliary N-terminal region, followed by two well defined and one degenerated RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), and a C-terminal RGG motif; hnRNP Q binds RNA through its RRM domains.