Alternative titles; symbols
HGNC Approved Gene Symbol: ARMCX1
Cytogenetic location: Xq22.1 Genomic coordinates (GRCh38) : X:101,550,547-101,554,700 (from NCBI)
Armadillo (arm) repeat-containing proteins, such as ARMCX1, are involved in development, maintenance of tissue integrity, and tumorigenesis. Their common feature is a 42-amino acid motif, the arm repeat (summary by Kurochkin et al., 2001).
Using a yeast 2-hybrid screen of a brain cDNA library to identify proteins interacting with the peroxisome protease PP110, Kurochkin et al. (2001) identified a cDNA encoding ARMCX1, which they called ALEX1. They also cloned a cDNA encoding ALEX1 by screening a testis cDNA library. By searching sequence databases for homologs of ALEX1, they identified cDNAs encoding ALEX2 (ARMCX2; 300363) and ALEX3 (ARMCX3; 300364). The predicted 453-amino acid ALEX1 protein contains a potential N-terminal transmembrane domain, 2 arm repeats, an ATP/GTP-binding site, and multiple phosphorylation sites. Northern blot and RT-PCR analyses revealed wide expression of a 2.2-kb ALEX1 transcript in normal tissues and cancer cell lines; no expression was detected in carcinomas. Kurochkin et al. (2001) proposed that the specific loss of expression in epithelial tissue tumors suggests that the ALEX proteins play a role in tumor suppression, possibly by being involved in the regulation of normal cell growth.
Lopez-Domenech et al. (2012) reported that mouse Armcx1 contains 456 amino acids and has an N-terminal signal peptide, followed by a mitochondrial targeting sequence, a nuclear localization signal, and 6 C-terminal arm repeats. In situ hybridization analysis showed that Armcx1 was highly expressed in mouse neuronal tissue. Epitope-tagged mouse Armcx1 localized to mitochondria of transfected HEK293 cells.
By genomic sequence analysis, Kurochkin et al. (2001) determined that the ARMCX1 gene contains 4 exons and spans 4.2 kb. The coding region resides entirely in exon 4.
By radiation hybrid analysis, Kurochkin et al. (2001) mapped the ARMCX1 gene to chromosome Xq21.33-q22.2.
By genomic sequence analysis, Lopez-Domenech et al. (2012) mapped the ARMCX1 gene to an ARMCX gene cluster on human chromosome Xq22.1 and mouse chromosome X. The cluster consists of 6 ARMCX genes and 1 pseudogene.
Lopez-Domenech et al. (2012) determined that the ARMCX genes are specific to all eutherian mammals, including the earliest branching armadillo. The ARMCX gene cluster originated at the beginning or early radiation of the most advanced eutherian mammals by retrotransposition of an ARMC10 (611864) mRNA followed by consecutive tandem duplication events. Appearance of the ARMCX cluster coincided with key innovations in the mammalian group, including origin of the well-developed placenta and increased complexity of the central nervous system and enlargement of the neocortex.
Kurochkin, I. V., Yonemitsu, N., Funahashi, S., Nomura, H. ALEX1, a novel human armadillo repeat protein that is expressed differentially in normal tissues and carcinomas. Biochem. Biophys. Res. Commun. 280: 340-347, 2001. [PubMed: 11162520] [Full Text: https://doi.org/10.1006/bbrc.2000.4125]
Lopez-Domenech, G., Serrat, R., Mirra, S., D'Aniello, S., Somorjai, I., Abad, A., Vitureira, N., Garcia-Arumi, E., Alonso, M. T., Rodriguez-Prados, M., Burgaya, F., Andreu, A. L., Garcia-Sancho, J., Trullas, R., Garcia-Fernandez, J., Soriano, E. The Eutherian Armcx genes regulate mitochondrial trafficking in neurons and interact with Miro and Trak2. Nature Commun. 3: 814, 2012. Note: Electronic Article. [PubMed: 22569362] [Full Text: https://doi.org/10.1038/ncomms1829]