(S (S (BASENP (DT This)) (VP (VBZ means) (SBAR (IN that) (S (NP (NP (BASENP (NN another) (JJ key) (NN function)) (PP (IN of) (BASENP (DT the) (NN mitochondria)))) (PRN (COLON -) (UCP (S (VP (TO to) (VP (VB activate) (NP (BASENP (DT an) (JJ abnormal) (NN cell) (POS 's)) (BASENP (JJ self-destruct) (NN mechanism)))))) (COMMA ,) (BASENP (NN apoptosis))) (COLON -))) (VP (VBZ is) (VP (ADVP (RB also)) (VBN blocked))))))) (PERIOD .))