RNA recognition motif 1 (RRM1) found in vertebrate insulin-like growth factor 2 mRNA-binding protein 3 (IGF2BP3)
This subgroup corresponds to the RRM1 of IGF2BP3 (IGF2 mRNA-binding protein 3 or IMP-3), also termed KH domain-containing protein overexpressed in cancer (KOC), or VICKZ family member 3, an RNA-binding protein that plays an important role in the differentiation process during early embryogenesis. It is known to bind to and repress the translation of IGF2 leader 3 mRNA. IGF2BP3 also acts as a Glioblastoma-specific proproliferative and proinvasive marker acting through IGF2 resulting in the activation of oncogenic phosphatidylinositol 3-kinase/mitogen-activated protein kinase (PI3K/MAPK) pathways. IGF2BP3 contains four hnRNP K-homology (KH) domains, two RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), and a RGG RNA-binding domain.