4GS0: Crystal Structure of Shp1 Catalytic Domain With Jak1 Activation Loop Peptide

SHP-1 (PTPN6) is a member of the SHP sub-family of protein tyrosine phosphatases and plays a critical role in the regulation of the JAK/STAT signaling pathway. Previous studies suggested that SHP-1 contains a PTP1B-like second phosphotyrosine pocket that allows for binding of tandem phosphotyrosine residues, such as those found in the activation loop of JAK kinases. To discover the structural nature of the interaction between SHP-1 and the JAK family member, JAK1, we determined the 1.8A co-crystal structure of the SHP-1 catalytic domain and a JAK1-derived substrate peptide. This structure reveals electron density for only one bound phosphotyrosine residue. To investigate the role of the predicted second site pocket we determined the structures of SHP-1 in complex with phosphate and sulfate to 1.37A and 1.7A, respectively, and performed anomalous scattering experiments for a selenate-soaked crystal. These crystallographic data suggest that SHP-1 does not contain a PTP1B-like second site pocket. This conclusion is further supported by analysis of the relative dephosphorylation and binding affinities of mono- and tandem-phosphorylated peptide substrates. The crystal structures instead indicate that SHP-1 contains an extended C-terminal helix alpha2' incompatible with the predicted second phosphotyrosine binding site. This study suggests that SHP-1 defines a new category of PTP1B-like protein tyrosine phosphatases with a hindered second phosphotyrosine pocket.
PDB ID: 4GS0Download
MMDB ID: 105960
PDB Deposition Date: 2012/8/27
Updated in MMDB: 2012/12 
Experimental Method:
x-ray diffraction
Resolution: 1.8  Å
Source Organism:
Similar Structures:
Biological Unit for 4GS0: monomeric; determined by author and by software (PISA)
Molecular Components in 4GS0
Label Count Molecule
Protein (1 molecule)
Tyrosine-protein Phosphatase Non-receptor Type 6
Molecule annotation
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Citing MMDB