ELAV-like protein (Hu antigen) (Hu)

The Hu proteins, also known as ELAV-like proteins (ELAVL1, ELAVL2, ELAVL3, and ELAVL4), are a family of highly conserved RNA-binding proteins primarily expressed in the central and peripheral nervous systems, with the exception of ELAVL1 (HuR) which is ubiquitously expressed (UniProt, 2024). These proteins play a critical role in neuronal development and maintenance by binding to AU-rich elements in the 3' untranslated regions of mRNAs, thereby regulating their stability, splicing, and translation (Lal et al., 2017). In clinical medicine, these proteins are the targets of 'Anti-Hu' autoantibodies (also known as ANNA-1), which are typically produced as a paraneoplastic response to tumors, most commonly small cell lung cancer (StatPearls, 2023). This autoimmune reaction leads to paraneoplastic neurological syndromes (PNS), such as paraneoplastic encephalomyelitis and sensory neuronopathy, caused by the immune system attacking neurons that express Hu proteins (Graus et al., 2001). While therapeutic strategies currently focus on treating the underlying malignancy and using immunosuppressants like Rituximab or IVIG to manage the autoimmune response, experimental small molecules like MS-444 are being investigated to inhibit Hu protein function in the context of oncology (Lal et al., 2017).

Other names

Hu antigenANNA-1Anti-neuronal nuclear antibody type 1ELAVL1ELAVL2ELAVL3ELAVL4HuDHuCHuBHuR

Therapeutic management primarily involves systemic immunosuppression to reduce autoantibody production and treating the underlying malignancy to eliminate the source of the Hu antigen; experimental small-molecule inhibitors target the RNA-binding domain of Hu proteins to disrupt mRNA stabilization in cancer cells (Lal et al., 2017; Graus et al., 2001).