THE REGIONS OF THE FE65 PROTEIN HOMOLOGOUS TO THE PHOSPHOTYROSINE INTERACTION PHOSPHOTYROSINE BINDING DOMAIN OF SHC BIND THE INTRACELLULAR DOMAIN OF THE ALZHEIMERS AMYLOID PRECURSOR PROTEIN

Fe65 is a protein mainly expressed in several districts of the mammali an nervous system, The search of protein sequence data banks revealed that Fe65 contains two phosphotyrosine interaction (PID) or phosphotyr osine binding (PTB) domains, previously identified in the Shc adaptor molecule. The two putative PID/PTB domains of Fe65 were used to constr uct glutathione S-transferase-Fe65 fusion proteins, Co-precipitation e xperiments demonstrated that the Fe65 PID/PTB domains interacted with several proteins of apparent molecular mass 135, 115, 105, and 51 kDa, The region of Fe65 containing the PID/PTB domains was used as a bait to screen a human brain cDNA library in yeast by the two-hybrid system , Three different cDNA clones were isolated, two of which contain over lapping segments of the cDNA encoding the COOH terminus of the Alzheim er's beta-amyloid-precursor protein (APP), that represents the short i ntracellular domain of this membrane protein, The third clone contains a cDNA fragment coding for the COOH terminus of the human counterpart of a mouse beta-amyloid-like precursor protein. The alignment of the three APP encoding cDNA fragments found in the screening suggests that the region of APP involved in the binding is centered on the NPTY seq uence, which is analogous to that present in the intracellular domains of the growth factor receptors interacting with the PID/PTB domain of Shc.