ELAV-like protein 4 (ELAVL4) (ELAVL4)

ELAV-like protein 4 (ELAVL4), also known as HuD, is a neuron-specific RNA-binding protein that plays a critical role in neuronal development, mRNA stability, and synaptic plasticity by binding to AU-rich elements in the 3' untranslated regions of target mRNAs (UniProt P26378). Isoaspartylation is a spontaneous post-translational modification where L-aspartyl or L-asparaginyl residues are converted to L-isoaspartyl residues, a process often associated with protein aging and cellular stress (Doyle et al., 2007). In the context of Paraneoplastic Neurological Syndromes (PNS), particularly anti-Hu syndrome, isoaspartylated ELAVL4 acts as a potent neoantigen that breaks immune tolerance, leading to the production of high-titer anti-Hu autoantibodies (Mamula et al., 2007). These autoantibodies are frequently associated with small cell lung cancer (SCLC) and result in extensive neuronal damage across the central and peripheral nervous systems (Graus et al., 2001). While ELAVL4 itself is a critical regulator of gene expression, its isoaspartylated form is a primary target for understanding autoimmune-mediated neurodegeneration and developing diagnostic biomarkers. Therapeutic strategies focus on enhancing the repair of such modifications via the enzyme Protein L-isoaspartyl methyltransferase (PIMT) or modulating the resulting immune response (Cimmino et al., 2008). Currently, there are no approved drugs that directly target the isoaspartylated form of ELAVL4, making it a subject of intense research in neuro-oncology.

Other names

HuDHu-antigen DPNM2Paraneoplastic encephalomyelitis antigen 2isoaspartyl-HuDisoaspartylated ELAVL4

The isoaspartylated form of ELAVL4 acts as a neoantigen, triggering an autoimmune response (anti-Hu syndrome) that leads to the production of autoantibodies and subsequent neuronal damage.