TASK DEFINITION: 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.
PROBLEM:  Furthermore , the SH2 domain of p56 ( lck ) appeared to be required for pervanadate - induced NF - kappa B activation but not for Tyr42 phosphorylation .

SOLUTION: SH2 domain

PROBLEM:  A stable and stoichiometric complex of CaMKIV with protein serine - threonine phosphatase 2A ( PP2A ) was identified in which PP2A dephosphorylates CaMKIV and functions as a negative regulator of CaMKIV signaling .

SOLUTION: negative regulator

PROBLEM:  The effective binding of medroxyprogesterone acetate to the glucocorticoid receptor was confirmed by direct binding studies utilizing a tritiated derivative of this steroid .

SOLUTION:
glucocorticoid receptor