+---------------SUBJ:V-N--------------+    
     +---------COMP:N-N(of)--------+       |    
     +COMP:N-N(of+          +MOD_AT+       |    
     |           |          |      |       |    
 Relation of __NODE__ and liver protein occurs .
COMP:N-N(of) (relation,__NODE__)
COMP:N-N(of) (relation,protein)
MOD_ATT:N-N (protein,liver)
SUBJ:V-N (occur,relation)