In this task, you are given a sentence. You are expected to recognize the name of gene or protein. Although there might be several correct answers, you need to write one of them.

[EX Q]:  By computed homology search , we noticed significant similarities between US3 PK and p21 - activated kinase ( PAK ) , which is activated by the Cdc42 or Rac .
[EX A]: US3 PK

[EX Q]:  The RTI40 gene spans 35 kilobase pairs ; it contains 6 exons and at least 6 rat Identifier repetitive elements .
[EX A]: RTI40 gene

[EX Q]:  Finally , the conservation of the two residues most sensitive to mutations ( Y949 and Y953 ) in TM11 , and in the homologous TM5 , of all mammalian P - gps and also in other ABC transporters , suggests that these residues and domains may play an important role in structural as well as mechanistic aspects common to this family of proteins .
[EX A]:
ABC transporters