passages.id: split_1_test_1937_passage
passages.type: progene_text
passages.text: Immunoblotting of lysates from an FSK - treated Th1 clone with antibodies to a carboxy - terminal epitope of p56 ( lck ) , a signal transduction enzyme upstream from ERK-1 and ERK2 , did not detect p56 ( lck ) unless the lysates were reduced prior to electrophoresis .