The Phosphotyrosine Interaction Domains of X11 and FE65 Bind to Distinct Sites on the YENPTY Motif of Amyloid Precursor Protein

Abstract

The phosphotyrosine interaction (PI) domains (also known as the PTB, or phosphotyrosine binding, domains) of Shc and IRS-1 are recently described domains that bind peptides phosphorylated on tyrosine residues. The PI/PTB domains differ from Src homology 2 (SH2) domains in that their binding specificity is determined by residues that lie amino terminal and not carboxy terminal to the phosphotyrosine. Recently, it has been appreciated that other cytoplasmic proteins also contain PI domains. We now show that the PI domain of X11 and one of the PI domains of FE65, two neuronal proteins, bind to the cytoplasmic domain of the amyloid precursor protein (␤APP). ␤APP is an integral transmembrane glycoprotein whose cellular function is unknown. One of the processing pathways of ␤APP leads to the secretion of A␤, the major constituent of the amyloid deposited in the brain parenchyma and vessel walls of Alzheimer's disease patients. We have found that the X11 PI domain binds a YENPTY motif in the intracellular domain of ␤APP that is strikingly similar to the NPXY motifs that bind the Shc and IRS-1 PI/PTB domains. Protein-protein interactions are important in signaling by many cell surface receptors. For example, activated growth factor receptors bind several signaling proteins in a phosphotyrosine-dependent fashion. Many of these signaling proteins contain Src homology 2 (SH2) domains that mediate the interaction with growth factor receptors by binding to specific phosphopeptide sequences present on the receptors (40, 45). Our laboratory has been cloning receptor-binding proteins by screening bacterial expression libraries with the tyrosine-phosphorylated epidermal growth factor (EGF) receptor. In general, this approach has led to the cloning of genes that encode SH2-domain proteins (33,36,39,47). However, recently, our group and others have identified a new phosphotyrosine interaction/phosphotyrosine binding (PI/PTB) domain in the protein Shc (3, 23, 28). Shc has an important role in tyrosine kinase signal transduction. Shc becomes tyrosine phosphorylated upon activation of many growth factors, cytokines, and G-protein-coupled receptors (12,14,32,41,43,55). The tyrosine phosphorylation of Shc allows it to bind Grb2, which begins a cascade leading to the activation of Ras and mitogenactivated protein kinase pathways (43). The PI/PTB domain found in the amino terminus of Shc appears to be crucial for the interaction of Shc with EGF receptor, nerve growth factor receptor, and insulin receptor (1,3,13,16,52,54).Although both PI/PTB domains and SH2 domains bind to phosphotyrosine-containing peptides, their binding specificities and tertiary structures are completely different (48,56,59). While SH2 domain binding specificity is determined by residues that lie carboxy terminal to the phosphotyrosine, the Shc PI/PTB domain specificity is determined by residues amino terminal to the phosphotyrosine. The binding specificity for the Shc PI/PTB is the sequence ⌿XNPXpY (where ⌿ is a hydrophobic residue, N is asparagine, P is proline, X...

Re-engineering the target specificity of the insulin receptor by modification of a PTB domain binding site

“…In the Shc and IRS-1 PTB domains di erent residues recognize the bound pTyr, suggesting that these individual PTB domains might have independently acquired an ability to recognize phosphorylated Tyr (Eck et al, 1996;Zhou et al, 1995). Consistent with this view, PTB domains from proteins such as X11, Fe65 and Numb can bind tightly to non-phosphorylated peptides (Borg et al, 1996;Fiore et al, 1995;Li et al, 1997), suggesting that PTB domains may have originally developed as modules that recognize peptides with bturn structures, independently of phosphorylation. The diversity of peptide ligands recognized by PTB domains, and the signi®cant biological functions attributed to PTB-containing proteins, makes it important to understand the speci®city of ligand recognition in vivo.…”

The Tek/Tie2 receptor signals through a novel Dok-related docking protein, Dok-R

“…FRS2 contains a putative PTB domain that is also related to the PTB domain of IRS-1 and, although it is not clear whether the interaction between the FGF receptor and FRS2 is direct, the FGF receptor does not contain an NPXY motif. Additionally, the PTB domain of Shc has been shown to interact with PTP-PEST through an NPLH motif (Charest et al, 1996) and the PTB domains of X11 and FE65 (Borg et al, 1996) have been shown to interact with non-phosphorylated NPXY motifs. Similarly, the PTB domain of Numb has been shown to interact with non-phosphorylated (Dho et al, 1998) and non-NPXY motif-containing Chien et al, 1998) targets.…”

Mint3/X11γ Is an ADP-Ribosylation Factor-dependent Adaptor that Regulates the Traffic of the Alzheimer's Precursor Protein from theTrans-Golgi Network

“…Such sorting motifs function by binding specific adaptors to facilitate their selective import into budding carriers and ensure specificity in cargo selection and coat recruitment. The highly conserved phosphotyrosine binding (PTB) domains in all three Mint proteins have been shown previously to bind directly to the YENPXY motif of APP (Borg et al, 1996(Borg et al, , 1998Zhang et al, 1997;Sastre et al, 1998;Tanahashi and Tabira, 1999;Tomita et al, 1999;Ho et al, 2002;Araki et al, 2003). Other PTB domain containing proteins have similarly been shown to bind APP, including the Fe65 (Sabo et al, 1999) family, Dab2 (Howell et al, 1999), JIP1b (King et al, 2004), and ARH (Noviello et al, 2003).…”

“…APP binds Mints via the YENPXY motif in its cytosolic tail (Borg et al, 1996;McLoughlin and Miller, 1996;Zhang et al, 1997;Okamoto and Sudhof, 1998) and in the absence of this motif cannot bind Mints (Tomita et al, 1999;Taru and Suzuki, 2004). We compared the post-Golgi traffic of wild-type APP 695 to that of APP 695 ⌬681-690 in HeLa cells, using the temperature block and release protocol for accumulating cargo at the TGN and following its exit, respectively.…”