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]:  Two sequences in the Tip protein were previously shown to be involved in binding to Lck .
[EX A]: Tip protein

[EX Q]:  One of the challenges in defining the molecular events regulated by Nef has been obtaining good expression of Nef protein in T cells .
[EX A]: Nef protein

[EX Q]:  Lyn is not required for the recruitment of Syk to the cross - linked receptor , but is required for the internalization of the clustered BCR complexes .
[EX A]:
BCR complexes