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Receptor protein tyrosine phosphatase micro: measuring where to stick

A Radu Aricescu1, Christian Siebold, E Yvonne Jones

  • 1Cancer Research UK Receptor Structure Research Group, University of Oxford, Henry Wellcome Building of Genomic Medicine, Division of Structural Biology, Roosevelt Drive, Oxford OX3 7BN, UK.

Biochemical Society Transactions
|March 28, 2008
PubMed

Insights

Receptor protein tyrosine phosphatase micro (RPTPmicro) uses its extracellular region to bind to itself, forming dimers. This adhesion mechanism may control the phosphatase

Area of Science:

  • Biochemistry
  • Molecular Biology
  • Cell Biology

Background:

  • Receptor protein tyrosine phosphatases (RPTPs) are cell-surface molecules with extracellular regions that influence their function.
  • RPTPmicro's extracellular region is known to mediate homophilic adhesion, but its structural basis was unclear.

Purpose of the Study:

  • To determine the crystal structure of the entire extracellular region of RPTPmicro.
  • To elucidate the structural mechanisms underlying RPTPmicro-mediated homophilic adhesion.

Main Methods:

  • Sequence analysis to identify domains within the extracellular region.
  • Crystal structure determination of the RPTPmicro extracellular region.
  • Analysis of the physical characteristics and dimensions of the resulting adhesion dimer.

Main Results:

  • The extracellular region of RPTPmicro comprises six domains: MAM, immunoglobulin-like, and four fibronectin type III repeats.
  • The crystal structure revealed the entire extracellular region forms a functional adhesion dimer.
  • The dimer's dimensions suggest a mechanism linking cell-cell spacing to phosphatase localization.

Conclusions:

  • The structure of the RPTPmicro extracellular region provides insights into its homophilic adhesion function.
  • The adhesion dimer formation is a key aspect of RPTPmicro's cell-surface interactions.
  • RPTPmicro localization and function may be regulated by the physical spacing between cells.

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