| Primary Identifier | IPR013625 | Type | Domain |
| Short Name | PTB |
| description | The phosphotyrosine-binding domain (PTB, also phosphotyrosine-interaction or PI domain) of tensin tends to be found at the C terminus. Tensin is a multi-domain protein that binds to actin filaments and functions as a focal-adhesion molecule (focal adhesions are regions of plasma membrane through which cells attach to the extracellular matrix). Human tensin has actin-binding sites, an SH2 () domain and a region similar to the tumour suppressor PTEN []. The PTB domain interacts with the cytoplasmic tails of beta integrin by binding to an NPXY motif []. The PTB domain is also found in the epidermal growth factor receptor kinase substrate 8 (EPS8).PTB domains have a common PH-like fold and are found in various eukaryotic signaling molecules []. This domain was initially shown to binds peptides with a NPXY motif with differing requirements for phosphorylation of the tyrosine, although more recent studies have found that some types of PTB domains can bind to peptides lack tyrosine residues altogether []. In contrast to SH2 domains, which recognize phosphotyrosine and adjacent carboxy-terminal residues, PTB-domain binding specificity is conferred by residues amino-terminal to the phosphotyrosine []. PTB domains are classified into three groups: phosphotyrosine-dependent Shc-like, phosphotyrosine-dependent IRS-like, and phosphotyrosine-independent Dab-like PTB domains []. |
