8j9s
leucine zipper complex of AIMP1 and AIMP2
Structural highlights
DiseaseAIMP1_HUMAN Defects in AIMP1 are the cause of leukodystrophy hypomyelinating type 3 (HLD3) [MIM:260600. A severe autosomal recessive hypomyelinating leukodystrophy characterized by early infantile onset of global developmental delay, lack of development, lack of speech acquisition, and peripheral spasticity associated with decreased myelination in the central nervous system.[1] FunctionAIMP1_HUMAN Non-catalytic component of the multisynthase complex. Stimulates the catalytic activity of cytoplasmic arginyl-tRNA synthase. Binds tRNA. Possesses inflammatory cytokine activity. Negatively regulates TGF-beta signaling through stabilization of SMURF2 by binding to SMURF2 and inhibiting its SMAD7-mediated degradation. Involved in glucose homeostasis through induction of glucagon secretion at low glucose levels. Promotes dermal fibroblast proliferation and wound repair. Regulates KDELR1-mediated retention of HSP90B1/gp96 in the endoplasmic reticulum. Plays a role in angiogenesis by inducing endothelial cell migration at low concentrations and endothelian cell apoptosis at high concentrations. Induces maturation of dendritic cells and monocyte cell adhesion. Modulates endothelial cell responses by degrading HIF-1A through interaction with PSMA7.[2] [3] [4] [5] [6] [7] Publication Abstract from PubMedAminoacyl-tRNA synthetases (ARSs) are responsible for the ligation of amino acids to their cognate tRNAs. In human, nine ARSs form a multi-tRNA synthetase complex (MSC) with three ARS-interacting multifunctional proteins (AIMPs). Among the components of MSC, arginyl-tRNA synthetase 1 (RARS1) and two AIMPs (AIMP1 and AIMP2) have leucine zipper (LZ) motifs, which they utilize for their assembly in an MSC. RARS1 and AIMP1 have two LZ motifs (LZ1 and LZ2) in their N-terminus, respectively, while AIMP2 has one LZ motif between its lysyl-tRNA synthetase 1 (KARS1)-binding motif and glutathione transferase-homology domain, which links aspartyl-tRNA synthetase 1 (DARS1). Although the interaction mode between AIMP1 and RARS1, which also binds glutaminyl-tRNA synthetase 1 (QARS1), has been revealed, the mode in the presence of AIMP2 is still ambiguous since AIMP2 is known to not only bind to AIMP1 but also form a homodimer through its LZ. Here, we determined a crystal structure of the LZ complex of AIMP1 and AIMP2 and revealed the interaction mode of a heterotrimeric complex of RARS1, AIMP1, and AIMP2. The complex is established by a three-stranded coiled-coil structure with RARS1 LZ1, AIMP1 LZ1, and AIMP2 LZ and is completed with a two-stranded coiled-coil structure of RARS1 LZ2 and AIMP1 LZ2. In the human MSC, this heterotrimeric complex of RARS1, AIMP1, and AIMP2 allows for a subcomplex of fourteen protein molecules, in which two QARS1-RARS1-AIMP1-AIMP2-2 x KARS1 complexes are linked separately to a dimeric DARS1. Assembly of the Human Multi-tRNA Synthetase Complex Through Leucine Zipper Motifs.,Kim DK, Lee K, Kang BS J Mol Biol. 2024 Nov 13;436(24):168865. doi: 10.1016/j.jmb.2024.168865. PMID:39542129[8] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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