“…In particular, studies in vitro with recombinant proteins and crystal structure determinations have shown that the core region of Nef, via a proline-rich motif, binds with a high affinity to the SH3 domains of Src-like protein-tyrosine kinases (Src-like PTKs) (14,22). Four members of the Src kinases family, p56 lck , p56/59 hck , p59 fyn , and p53 /56 lyn have been shown to be able to interact physically with Nef (14,(22)(23)(24)(25). Interestingly, the affinity of Nef-p56/59 hck interaction is the highest known for an SH3-mediated proteinprotein binding (23).…”