Paraneoplastic Ma antigen 2 (PNMA2)

Paraneoplastic Ma antigen 2 (PNMA2) is a neuronal protein encoded by the PNMA2 gene, predominantly expressed in the central nervous system under normal conditions[1][2][3][4]. Structurally, it is derived from a Ty3 retrotransposon and self-assembles into non-enveloped, icosahedral virus-like capsids, a property it shares with retroviral Gag proteins[1][3][5]. While its natural physiological role remains unclear, PNMA2 can be ectopically expressed in certain tumors. When this occurs, its capsid assembly can provoke strong autoantibody-mediated immune responses, underlying the rare but severe anti-Ma2 paraneoplastic neurological syndrome characterized by rapid memory loss and cognitive decline due to autoimmune attack on the brain[1][3][4]. PNMA2 autoantibodies serve as highly specific biomarkers for some paraneoplastic conditions, including neuroendocrine tumors[2]. Recent structural studies have enabled the engineering of PNMA2 capsids to deliver mRNA into cells, raising potential for therapeutic applications in nucleic acid delivery, although this is not yet used clinically[5]. There are no known drugs that directly target PNMA2, and therapeutic activity generally revolves around detection (as a biomarker) or managing the consequences of autoimmunity.

Other names

MA2MM2RGAG2KIAA088340 kDa neuronal proteinOnconeuronal antigen Ma2Paraneoplastic neuronal antigen MM2Retrotransposon Gag domain containing 2Paraneoplastic Ma antigen 2Onconeuronal antigen MA2