ShcA , a signaling phospho protein , human polyhomeotic 2 ( HPH 2 ) , a transcriptional regulator , and highly similar to smoothelin ( HSTS ) , which is related to the cytoskeletal associated protein smoothelin , interact specifically with MK 2 . ^^^ The interaction of MK 2 with the 66 kDa isoform of ShcA , p 66 ( ShcA ) , and HPH 2 was confirmed using co immunoprecipitation . ^^^