LARP RNA-binding protein that regulates the translation of specific target mRNA species downstream of the mTORC1 complex, in function of growth signals and nutrient availability. Interacts on the one hand with the 3' poly-A tails that are present in all mRNA molecules, and on the other hand with the 7-methylguanosine cap structure of mRNAs containing a 5' terminal oligopyrimidine (5'TOP) motif, which is present in mRNAs encoding ribosomal proteins and several components of the translation machinery. The interaction with the 5' end of mRNAs containing a 5'TOP motif leads to translational repression by preventing the binding of EIF4G1. When mTORC1 is activated, LARP1 is phosphorylated and dissociates from the 5' untranslated region (UTR) of mRNA. Does not prevent binding of EIF4G1 to mRNAs that lack a 5'TOP motif. Interacts with the free 40S ribosome subunit and with ribosomes, both monosomes and polysomes. Under normal nutrient availability, interacts primarily with the 3' untranslated region (UTR) of mRNAs encoding ribosomal proteins and increases protein synthesis. Associates with actively translating ribosomes and stimulates translation of mRNAs containing a 5'TOP motif, thereby regulating protein synthesis, and as a consequence, cell growth and proliferation. Stabilizes mRNAs species with a 5'TOP motif, which is required to prevent apoptosis. (Microbial infection) Positively regulates the replication of dengue virus (DENV). Belongs to the LARP family. 2 alternatively spliced human isoforms have been reported. Note: This description may include information from UniProtKB.
Protein type: RNA-binding
Chromosomal Location of mouse Ortholog: 11|11 B1.3
Cellular Component:  cytoplasm; cytoplasmic stress granule
Molecular Function:  eukaryotic initiation factor 4E binding; mRNA 3'-UTR binding; mRNA 5'-UTR binding; ribosomal small subunit binding; RNA 7-methylguanosine cap binding; RNA binding; RNA cap binding; translation activator activity; translation initiation factor binding
Biological Process:  cell proliferation; cellular response to rapamycin; mRNA stabilization; negative regulation of translation; negative regulation of translational initiation; positive regulation of macroautophagy; positive regulation of viral genome replication; regulation of translation; response to amino acid starvation; TOR signaling; TORC1 signaling; translational initiation
Reference #:  Q6ZQ58 (UniProtKB)
Alt. Names/Synonyms: 1810024J12Rik; 3110040D16Rik; Kiaa0731; la related protein; La ribonucleoprotein domain family member 1; La ribonucleoprotein domain family, member 1; La-related protein 1; Larp; Larp1; mKIAA0731
Gene Symbols: Larp1
Molecular weight: 121,125 Da
Basal Isoelectric point: 8.87  Predict pI for various phosphorylation states
Protein-Specific Antibodies, siRNAs or Recombinant Proteins from Cell Signaling Technology® Total Proteins
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Protein Structure Not Found.

Cross-references to other databases:  AlphaFold  |  STRING  |  BioGPS  |  Pfam  |  Phospho.ELM  |  NetworKIN  |  UniProtKB  |  Entrez-Gene  |  GenPept  |  Ensembl Gene