The reference OMIM entry for this protein is 600859

Aminoacyl trna synthetase complex-interacting multifunctional protein 2; aimp2
Jtv1 gene
Trna synthetase cofactor p38; p38

CLONING

In the process of characterizing PMS2 (600259) and its promoter region, Nicolaides et al. (1995) discovered another gene, designated JTV1, that is transcribed from the opposite strand and overlaps with PMS2. Both are ubiquitously expressed, as assayed by RT-PCR. JTV1 encodes a predicted 312-amino acid protein. The authors noted that protein sequence showed limited identity to the glutathione S-transferases (e.g., GSTM1; 138350). In eukaryotes, 9 aminoacyl-tRNA synthetases contribute to a multienzyme complex of defined and conserved structural organization. This ubiquitous multiprotein assemblage comprises a unique bifunctional aminoacyl-tRNA synthetase, glutamyl-prolyl-tRNA synthetase (138295), as well as the monospecific isoleucyl- (600709), leucyl- (151350), glutaminyl- (603727), methionyl- (156560), lysyl- (601421), arginyl- (107820), and aspartyl- (603084) tRNA synthetases. Three auxiliary proteins of apparent molecular masses of 18, 38, and 43 kD are invariably associated with the 9 tRNA synthetase components of the complex. Quevillon et al. (1999) isolated the cDNA encoding the p38 non-synthetase component. By examination of genomic sequences, they showed that the 320-amino acid protein has no homolog in yeast, bacteria, or archaea. The p38 protein is a moderately hydrophobic protein, displays a putative leucine-zipper motif, and shares a sequence pattern with protein domains that are involved in protein-protein interactions. p38 was found to associate with itself to form a dimer, but also with p43, with the class I tRNA synthetases arginyl-tRNA synthetase (ArgRS) and GlnRS, with the class II synthetases AspRS and LysRS, and with the bifunctional GluProRS.

GENE STRUCTURE

Nicolaides et al. (1995) determined that the JTV1 and PMS2 genes lie in a head-to-head arrangement. The JTV1 gene is transcribed from the opposite strand of the PMS2 gene.

GENE FUNCTION

The tRNA synthetase cofactor p38 was first identified as a factor associated with a macromolecular protein complex consisting of several different aminoacyl-tRNA synthetases (Quevillon et al., 1999). Kim et al. (2002) showed that p38 is a scaffold required for the assembly and stability of the multi-tRNA synthetase complex. Mice that were homozygous, but not heterozygous, with respect to mutations in p38 showed neonatal lethality, although they were born alive with the normal segregation ratio. Kim et al. (2003) investigated the molecular mechanisms underlying lethality of p38-mutant mice. p38 was found to interact with FUSE-binding protein (FBP; 603444), a transcriptional activator of MYC (190080). Binding of p38 stimulated ubiquitination and degradation of FBP, leading to downregulation of MYC, which is required for differentiation of functional alveolar type II cells. Transforming growth factor-beta (190180) induced p38 expression and promoted its translocation to nuclei for the regulation of FBP and MYC. Thus, this work identified a new activity of p38 as a mediator of TGF-beta signaling and its functional importance in the control of MYC during lung differentiation. Alveolar type II cells are important for pulmonary respiration because they secrete surfactants that reduce the surface tension of water on the alveolar surface. Incomplete differentiation of these cells may cause respiratory distress syndrome, which occurs frequently in preterm infants and is a principal cause of their death. Corti et al. (2003) demonstrated that parkin (60 ... More on the omim web site

Subscribe to this protein entry history

June 29, 2020: Protein entry updated
Automatic update: OMIM entry 600859 was added.

Oct. 19, 2018: Additional information
Initial protein addition to the database. This entry was referenced in Bryk and co-workers. (2017).