DOK7 (Downstream of kinase 7) is a 55kD member of the DOK family of cytoplasmic adaptor proteins. It links the acetylcholine receptor and the receptor tyrosine kinase MuSK in skeletal and cardiac muscle. Mutations can cause familial myasthenic syndromes. The 504aa human DOK7 contains pleckstrin homology (aa7-109) and phosphotyrosine-binding (PTK,(aa125-236) and SH2 domains and a C-terminal nuclear export signal. Splicing isoforms of 255, 608 and 366aa diverge at aa175 or 500, or have 40 divergent aa replacing (aa1-178), respectively. Within (aa179-299), human DOK7 shares 92% and 93% aa identity with mouse and rat DOK7, respectively.