scholarly journals Regulation of Cell Adhesion by Protein-tyrosine Phosphatases

2006 ◽  
Vol 281 (23) ◽  
pp. 15593-15596 ◽  
Author(s):  
Keith Burridge ◽  
Sarita K. Sastry ◽  
Jennifer L. Sallee
2021 ◽  
Vol 478 (5) ◽  
pp. 1061-1083
Author(s):  
Katherine A. Young ◽  
Laura Biggins ◽  
Hayley J. Sharpe

Adhesive structures between cells and with the surrounding matrix are essential for the development of multicellular organisms. In addition to providing mechanical integrity, they are key signalling centres providing feedback on the extracellular environment to the cell interior, and vice versa. During development, mitosis and repair, cell adhesions must undergo extensive remodelling. Post-translational modifications of proteins within these complexes serve as switches for activity. Tyrosine phosphorylation is an important modification in cell adhesion that is dynamically regulated by the protein tyrosine phosphatases (PTPs) and protein tyrosine kinases. Several PTPs are implicated in the assembly and maintenance of cell adhesions, however, their signalling functions remain poorly defined. The PTPs can act by directly dephosphorylating adhesive complex components or function as scaffolds. In this review, we will focus on human PTPs and discuss their individual roles in major adhesion complexes, as well as Hippo signalling. We have collated PTP interactome and cell adhesome datasets, which reveal extensive connections between PTPs and cell adhesions that are relatively unexplored. Finally, we reflect on the dysregulation of PTPs and cell adhesions in disease.


2006 ◽  
Vol 281 (24) ◽  
pp. 16189-16192 ◽  
Author(s):  
Jennifer L. Sallee ◽  
Erika S. Wittchen ◽  
Keith Burridge

1998 ◽  
Vol 77 (1) ◽  
pp. 59-62 ◽  
Author(s):  
Roel Q.J. Schaapveld ◽  
Jan T.G. Schepens ◽  
Dietmar Bächner ◽  
Joline Attema ◽  
Bé Wieringa ◽  
...  

2019 ◽  
Author(s):  
Iain M. Hay ◽  
Gareth W. Fearnley ◽  
Pablo Rios ◽  
Maja Köhn ◽  
Hayley J. Sharpe ◽  
...  

ABSTRACTThe dynamic regulation of protein tyrosine phosphorylation is a critical feature of intercellular communication and is regulated by the actions of kinases and phosphatases. The receptor-linked protein tyrosine phosphatases (RPTPs) are key signaling molecules that possess an extracellular domain and intracellular phosphatase domains. Most human RPTPs have tandem intracellular tyrosine phosphatase domains: a catalytically active membrane proximal (D1) domain; and a membrane distal (D2) inactive “pseudophosphatase” domain. The receptor PTPRU plays a role in development, multiple cancers and has been implicated in the dephosphorylation of cell adhesion proteins. However, PTPRU has a non-canonical D1 domain containing several sequence variations in key catalytic loops that suggest it may function using a mechanism distinct from related RPTPs. Here, we demonstrate through biochemical and structural studies that PTPRU is unique amongst the RPTPs in possessing two pseudophosphatase domains. We show that PTPRU-D1 displays no detectable catalytic activity against a range of phosphorylated substrates and determine that this is due to substantial disorder in the substrate-binding pocket as well as rearrangement of the catalytic loop such that the active site cysteine is occluded. We also show that this cysteine can form an intramolecular disulfide bond with a vicinal “backdoor” cysteine. Further, we demonstrate that the PTPRU D2 domain can recruit substrates of related RPTPs suggesting that this pseudophosphatase functions by competing with active phosphatases for the binding of substrates involved in cell adhesion. Therefore, PTPRU is a bona-fide pseudophosphatase and its functional role in cell signaling is via a non-catalytic mechanism.SIGNIFICANCE STATEMENTProtein tyrosine phosphorylation is a key post-translational modification required for cellular communication that is dynamically regulated by the activities of tyrosine kinases and phosphatases. Receptor tyrosine phosphatases (RPTPs) possess an extracellular receptor domain and intracellular phosphatase domains. We show that PTPRU is a non-canonical RPTP devoid of catalytic activity and demonstrate that this is due to multiple structural rearrangements. Despite this, PTPRU retains the capacity to bind the substrates of related phosphatases suggesting that the non-catalytic function of this pseudophosphatase is to compete with active phosphatases for the binding of substrates. Such pseudoenzymes represent an exciting and growing area of research with implications as key regulators of signaling networks.


Sign in / Sign up

Export Citation Format

Share Document