Crystal Structure of the Human Fe65-PTB1 Domain

Irmgard Sinning,Stéphanie Ravaud,Klemens Wild,Sabine Schlesinger,Jens Radzimanowski,Konrad Beyreuther,Joachim Koch

doi:10.1074/jbc.m800861200

Irmgard Sinning, Stéphanie Ravaud + Show 5 more

Open Access

https://doi.org/10.1074/jbc.m800861200

Copy DOI

Abstract

The neuronal adaptor protein Fe65 is involved in brain development, Alzheimer disease amyloid precursor protein (APP) signaling, and proteolytic processing of APP. It contains three protein-protein interaction domains, one WW domain, and a unique tandem array of phosphotyrosine-binding (PTB) domains. The N-terminal PTB domain (Fe65-PTB1) was shown to interact with a variety of proteins, including the low density lipoprotein receptor-related protein (LRP-1), the ApoEr2 receptor, and the histone acetyltransferase Tip60. We have determined the crystal structures of human Fe65-PTB1 in its apo- and in a phosphate-bound form at 2.2 and 2.7A resolution, respectively. The overall fold shows a PTB-typical pleckstrin homology domain superfold. Although Fe65-PTB1 has been classified on an evolutionary basis as a Dab-like PTB domain, it contains attributes of other PTB domain subfamilies. The phosphotyrosine-binding pocket resembles IRS-like PTB domains, and the bound phosphate occupies the binding site of the phosphotyrosine (Tyr(P)) within the canonical NPXpY recognition motif. In addition Fe65-PTB1 contains a loop insertion between helix alpha2 and strand beta2(alpha2/beta2 loop) similar to members of the Shc-like PTB domain subfamily. The structural comparison with the Dab1-PTB domain reveals a putative phospholipid-binding site opposite the peptide binding pocket. We suggest Fe65-PTB1 to interact with its target proteins involved in translocation and signaling of APP in a phosphorylation-dependent manner.

Highlights

One N-terminal WW domain and two contiguous C-terminal phosphotyrosine-binding domains (PTB1 and PTB2)
The Fe65-PTB1 domain has been shown to interact with the low density lipoprotein receptorrelated protein (LRP-1) [5], the ApoEr2 receptor [6], the histone acetyltransferase Tip60 [7], and the transcription factor CP2/LSF/LBP1 [8], whereas Fe65-PTB2 interacts with the amyloid precursor protein (APP) intracellular domain [9]
The described interactions with Tip60 and CP2/LSF/LBP1 are important for the regulation of gene expression [7, 8], whereas the interaction with the C-terminal domain of LRP-1 has been shown to play a critical role for APP localization and processing [5] and for Alzheimer disease pathogenesis

Summary

Introduction

One N-terminal WW domain and two contiguous C-terminal phosphotyrosine-binding domains (PTB1 and PTB2). The ␣1-helix located at the N terminus of Shc- and Dab-like PTB domains (Fig. 1B and Fig. 2) is not present in the Fe65PTB1 structure and is not predicted on the sequence level. In the P212121 space group this loop is like PTB domains require phosphorylated tyrosines for high involved in crystal contacts and is part of the model.

Results

Conclusion