Protein: Insulin-like growth factor 2 mRNA-binding protein 1 (IGF2 mRNA-binding protein 1) (IMP-1) (IGF-II mRNA-binding protein 1) (VICKZ family member 1) (Zip-code binding polypeptide) (Zipcode-binding protein 1) (ZBP-1) (O42254)
Organism: Gallus gallus (Chicken)
Function: RNA-binding factor that recruits target transcripts to cytoplasmic protein-RNA complexes (mRNPs). This transcript 'caging' into mRNPs allows mRNA transport and transient storage. It also modulates the rate and location at which target transcripts encounter the translational apparatus and shields them from endonuclease attacks or microRNA-mediated degradation. Preferentially binds to N6-methyladenosine (m6A)-containing mRNAs and increases their stability (By similarity). Plays a direct role in the transport and translation of transcripts required for axonal regeneration in adult sensory neurons (By similarity). Regulates localized beta-actin/ACTB mRNA translation in polarized cells, a crucial process for cell migration and neurite outgrowth. Co-transcriptionally associates with the ACTB mRNA in the nucleus. This binding involves by a conserved 54-nucleotide element in the ACTB mRNA 3'-UTR, known as the 'zipcode'. The ribonucleoparticle (RNP) thus formed is exported to the cytoplasm, binds to a motor protein and is transported along the cytoskeleton to the cell periphery. During transport, IGF2BP1 prevents beta-actin mRNA from being translated into protein. When the RNP complex reaches its destination near the plasma membrane, IGF2BP1 is phosphorylated by SRC. This releases the mRNA, allowing ribosomal 40S and 60S subunits to assemble and initiate ACTB protein synthesis. The monomeric ACTB protein then assembles into the subcortical actin cytoskeleton, which pushes the leading edge onwards. Binds MYC mRNA. Binding to MYC mRNA is enhanced by m6A-modification of the CRD (By similarity). Promotes the directed movement of cells by fine-tuning intracellular signaling networks. Binds to MAPK4 3'-UTR and inhibits its translation. Interacts with PTEN transcript open reading frame (ORF) and prevents mRNA decay. This combined action on MAPK4 (down-regulation) and PTEN (up-regulation) antagonizes HSPB1 phosphorylation, consequently it prevents G-actin sequestration by phosphorylated HSPB1, allowing F-actin polymerization. Hence enhances the velocity of cell migration and stimulates directed cell migration by PTEN-modulated polarization.
Subcellular location: Nucleus. Cytoplasm. Cytoplasm, perinuclear region. Cytoplasm, P-body {ECO:0000250|UniProtKB:Q9NZI8}. Cytoplasm, Stress granule {ECO:0000250|UniProtKB:Q9NZI8}. Cell projection, growth cone. Cell projection, filopodium. Cell projection, lamellipodium. Note=In the nucleus, located in discrete foci, coinciding with the sites of ACTB transcription. Export from the nucleus is mediated by XPO1. In the cytoplasm, colocalizes with ACTB mRNA at the leading edge, in growth cone filopodia and along neurites. In these locations, also colocalizes with microtubules. Colocalization with ACTB mRNA is partially lost at the cell periphery, suggesting release of the transcript. In neuronal processes, exhibits fast retrograde and anterograde movements, when associated with ACTB mRNA; this motility is lost when the association is inhibited. In migrating fibroblasts, localizes not only to leading edges, but also to retracting tails. In response to cellular stress, such as oxidative stress or heat shock, recruited to stress granules.
Interaction partners:
- Actin, cytoplasmic 1
- Insulin-like growth factor 2
- Uncharacterized protein.
- Zinc finger and BTB domain containing 47.
- ELAV-like protein
- Heterogeneous nuclear ribonucleoprotein U.
- Fragile X messenger ribonucleoprotein 1
Sequence:
MNKLYIGNLNESVTPADLEKVFNDHKISFSGQFLVKSGYAFVDCPDEQWAMKAIETFSGKVELHGKQLEIEHSVPKKQRSRKIQIRNIPPQLRWEVLDGLLAQYGTVENCEQVNTDSETAVVNVTYTNREQTRQAIMKLNGHQLENHVLKVSYIPDEQSVQGPENGRRGGFGARGAPRQGSPVTAGAPVKQQPVDIPLRLLVPTQYVGAIIGKEGATIRNITKQTQSKIDVHRKENAGAAEKAISIHSTPEGCSAACKMILEIMQKEAKDTKTADEVPLKILAHNNFVGRLIGKEGRNLKKVEQDTETKITISSLQDLTLYNPERTITVKGSIENCCKAEQEIMKKVREAYENDVAAMSLQSHLIPGLNLAAVGLFPASSNAVPPPPSSVSGAAPYSSFMPPEQETVHVFIPAQAVGAIIGKKGQHIKQLSRFASASIKIAPPETPDSKVRMVVITGPPEAQFKAQGRIYGKLKEENFFGPKEEVKLETHIRVPASAAGRVIGKGGKTVNELQNLTAAEVVVPRDQTPDENEQVIVKIIGHFYASQMAQRKIRDILAQVKQQHQKGQSGQLQARRK