passages.id: split_4_test_975_passage
passages.type: progene_text
passages.text: To determine whether predicted transmembrane helices M4 , M5 , M6 , or M8 in SERCA1a interact with PLN , SERCA1a mutants were co - expressed with wild - type PLN and effects on Ca(2+) dependence of Ca(2+) transport were measured .