The inducible tyrosine kinase (ITK) is a critical regulator of signal transduction in T cells. The mechanism of its activation involves interactions with other signaling partners such as the adaptor protein SLP-76. ITK's SH3 domain interacts with the proline rich region (residues 184-195) of SLP-76 and this event is necessary for complete transphosphorylation and full activation of ITK. Our laboratory has devised a short cationic peptide (R9-QQP) that represents a portion the proline rich region of SLP-76 that contacts the SH3 domain of ITK. This peptide enters cells and displaces the interaction between SLP-76 and ITK. In pursuit of improved alternatives that exhibit better bioavailability and stability than the R9-QQP peptide, screening tools were designed with the intention of finding these alternative candidates that may bind to the target SH3 domain with greater affinity and provide potential therapeutics for diseases where ITK might be involved such as bronchial asthma.