Alternative titles; symbols
HGNC Approved Gene Symbol: ARMCX2
Cytogenetic location: Xq22.1 Genomic coordinates (GRCh38) : X:101,655,281-101,659,850 (from NCBI)
Armadillo (arm) repeat proteins, such as ARMCX2, 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)
By screening brain cDNA libraries for cDNAs capable of encoding large proteins, Nagase et al. (1998) isolated a cDNA encoding KIAA0512. The deduced 632-amino acid protein has homology to alpha-1 collagen type III (120180). RT-PCR analysis detected wide expression, with highest levels in kidney and ovary. Expression was undetectable in liver, pancreas, spleen, thymus, and testis.
By searching sequence databases for homologs of ALEX1 (ARMCX1; 300362), Kurochkin et al. (2001) identified cDNAs encoding ALEX2 and ALEX3 (ARMCX3; 300364). ALEX2, which is identical to KIAA0512, is 72% similar to the C-terminal part of ALEX1. It contains a potential N-terminal transmembrane domain and a single arm repeat. Northern blot and RT-PCR analyses revealed wide expression of a 2.7-kb ALEX2 transcript in normal tissues and cancer cell lines; expression was not detected in carcinomas. A transcript of 1.4-kb was prominent in skeletal muscle, testis, and placenta, while a 7.0-kb transcript was found in brain. The authors stated that the coding region is on a single exon. 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 Armcx2 contains 784 amino acids and has an N-terminal signal peptide, followed by a nuclear localization signal, a mitochondrial targeting sequence, and 6 C-terminal arm repeats. In situ hybridization analysis showed that Armcx2 was highly expressed in mouse neuronal tissue. Epitope-tagged mouse Armcx2 localized to mitochondria of transfected HEK293 cells.
Kurochkin et al. (2001) determined that the coding sequence of ARMCX2 is contained within 1 exon.
Nagase et al. (1998) mapped the KIAA0512 gene to the X chromosome by radiation hybrid analysis. Kurochkin et al. (2001) refined the localization to Xq21.33-q22.2.
By genomic sequence analysis, Lopez-Domenech et al. (2012) mapped the ARMCX2 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.
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]
Nagase, T., Ishikawa, K., Miyajima, N., Tanaka, A., Kotani, H., Nomura, N., Ohara, O. Prediction of the coding sequences of unidentified human genes. IX. The complete sequences of 100 new cDNA clones from brain which can code for large proteins in vitro. DNA Res. 5: 31-39, 1998. [PubMed: 9628581] [Full Text: https://doi.org/10.1093/dnares/5.1.31]