title: Cellular biochemistry methods for investigating protein tyrosine phosphatases.
abstract: CONCLUSIONS
  The protein tyrosine phosphatases (PTPs) are a family of proteins that play critical roles in cellular signaling and influence many aspects of human health and disease. Although a wealth of information has been collected about PTPs since their discovery, many questions regarding their regulation and function still remain.
  
  
  RESULTS
  Of particular importance are the elucidation of the biological substrates of individual PTPs and understanding of the chemical and biological basis for temporal and spatial resolution of PTP activity within a cell.
  
  
  BACKGROUND
  Drawing from recent advances in both biology and chemistry, innovative approaches have been developed to study the intracellular biochemistry and physiology of PTPs. We provide a summary of PTP-tailored techniques and approaches, emphasizing methodologies to study PTP activity within a cellular context. We first provide a discussion of methods for identifying PTP substrates, including substrate-trapping mutants and synthetic peptide libraries for substrate selectivity profiling. We next provide an overview of approaches for monitoring intracellular PTP activity, including a discussion of mechanistic-based probes, gel-based assays, substrates that can be used intracellularly, and assays tied to cell growth. Finally, we review approaches used for monitoring PTP oxidation, a key regulatory pathway for these enzymes, discussing the biotin switch method and variants of this approach, along with affinity trapping techniques and probes designed to detect PTP oxidation.
  
  
  CONCLUSIONS
  Further development of approaches to investigate the intracellular PTP activity and functions will provide specific insight into their mechanisms of action and control of diverse signaling pathways.
authors.affiliation: 1 Division of Cellular Biology, La Jolla Institute for Allergy and Immunology , La Jolla, California.
authors.forename: Stephanie M
authors.initials: SM
authors.lastname: Stanford
authors.forename: Vanessa
authors.initials: V
authors.lastname: Ahmed
authors.forename: Amy M
authors.initials: AM
authors.lastname: Barrios
authors.forename: Nunzio
authors.initials: N
authors.lastname: Bottini
mesh_terms: D000818:Animals; D001671:Biochemistry / Q000379:methods*; D057075:Enzyme Assays / Q000379:methods*; D006801:Humans; D015335:Molecular Probes; D010084:Oxidation-Reduction; D017027:Protein Tyrosine Phosphatases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D013379:Substrate Specificity
chemical_list: D015335:Molecular Probes; D017027:Protein Tyrosine Phosphatases