NXP-2

Product Information

Myositis-specific antibodies (MSAs) are an effective auxiliary tool for diagnosing patients with idiopathic inflammatory myopathies as specific autoantibodies are generally mutually exclusive and associated with distinct clinical subgroups and prognoses.

Anti-nuclear matrix protein 2 (anti-NXP2) is a key marker for juvenile dermatomyositis (JDM).  In JDM, this autoantibody is associated with severe, chronic muscle disease, including dysphagia, calcinosis, polyarthritis, intestinal vasculitis, and myalgia but a lower risk of interstitial lung disease. Cohort studies have found anti-NXP2 antibodies in around 25% of JDM patients.

Anti-NXP2 antibodies are also present in certain cohorts of adult dermatomyositis patients and have been linked to cancer-associated dermatomyositis.

NXP2 protein, also known as MJ or MORC3 is a 107 kDa nuclear matrix associated protein with three structural domains: GHKL ATPase, CW-type zinc-finger, and a coiled coil domain. It has roles in RNA metabolism and maintenance of nuclear architecture as well as transcription regulation and p53 protein activation. The epitopes of the protein are not currently known.

AROTEC NXP2 is a full length, soluble, folded form of the human NXP2 protein with a hexahistidine tag. It is produced in insect cells using the baculovirus expression system.

Clinical Indications

Dermatomyositis (DM)

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MSDS

References

1. Gunawardena H, Betteridge ZE, McHugh NJ. Newly identified autoantibodies: relationship to idiopathic inflammatory myopathy subsets and pathogenesis. Current Opinion in Rheumatology. 2008;20(6):675-680. doi:10.1097/BOR.0b013e328313bff4
2. Espada G, Maldonado Cocco Ja, Fertig N, Oddis Cv. Clinical and Serologic Characterization of an Argentine Pediatric Myositis Cohort: Identification of a Novel Autoantibody (anti-MJ) to a 142-kDa Protein. The Journal of Rheumatology. 2009;36(11):2547-2551. doi:10.3899/jrheum.090461
3. Oddis CV. Clinical and serological characterization of the anti-MJ antibody in childhood myositis. Arthritis Rheum. 1997 1997;40(9):S139.
4. Targoff I N. Sera with autoantibodies to the MJ antigen react with NXP2. Arthritis Rheum. 2007 2007;56:S787.
5. Gunawardena H, Wedderburn LR, Chinoy H, et al. Autoantibodies to a 140-kd protein in juvenile dermatomyositis are associated with calcinosis. Arthritis & Rheumatism. 2009;60(6):1807-1814. doi:https://doi.org/10.1002/art.24547
6. Fiorentino DF, Chung LS, Christopher-Stine L, et al. Most Patients With Cancer-Associated Dermatomyositis Have Antibodies to Nuclear Matrix Protein NXP-2 or Transcription Intermediary Factor 1γ. Arthritis & Rheumatism. 2013;65(11):2954-2962. doi:https://doi.org/10.1002/art.38093
7. Zhang Y, Klein BJ, Cox KL, et al. Mechanism for autoinhibition and activation of the MORC3 ATPase. Proceedings of the National Academy of Sciences. 2019;116(13):6111-6119. doi:doi:10.1073/pnas.1819524116
8. Takahashi K, Yoshida N, Murakami N, et al. Dynamic Regulation of p53 Subnuclear Localization and Senescence by MORC3. Molecular Biology of the Cell. 2007;18(5):1701-1709. doi:10.1091/mbc.e06-08-0747