Ligand Of Numb Protein X1 (LNX1)

LNX1 encodes a membrane-bound protein that is involved in signal transduction and protein interactions. The encoded product is an E3 ubiquitin-protein ligase, which mediates ubiquitination and subsequent proteasomal degradation of proteins containing phosphotyrosine binding (PTB) domains. This protein may play an important role in tumorogenesis. Alternatively spliced transcript variants encoding distinct isoforms have been described. A pseudogene, which is located on chromosome 17, has been identified for this gene.  LNX1 contains an N-terminal PTB domain-binding motif and 4 PDZ domains. It shares 88% identity with the shorter mouse Lnx1 isoform. Northern blot analysis detected a 2.8-kb transcript in heart, placenta, kidney, and pancreas, and transcripts of 2.6 and 4.0 kb only in brain.