+-MOD_ATT:N-ADJ+                                            
    |     +MOD_ATT:+MOD_PRED:N-A+COMP:ADJ-N(for+COMP:N-N(of+    
    |     |        |            |              |           |    
 __SP__ PCDHB protein(s) is necessary for interaction of cells .
MOD_ATT:N-ADJ (protein(s),__SP__)
MOD_ATT:N-N (protein(s),PCDHB)
MOD_PRED:N-ADJ (protein(s),necessary)
COMP:ADJ-N(for) (necessary,interaction)
COMP:N-N(of) (interaction,cell)