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Intramolecular interactions in protein tyrosine phosphatase RPTPmu: kinetic evidence

Aricescu, Alexandru R.; Fulga, Tudor A.; Cismasiu, Valeriu LU ; Goody, Roger S. and Szedlacsek, Stefan E. (2001) In Biochemical and Biophysical Research Communications 280(1). p.319-327
Abstract
The receptor-like protein tyrosine phosphatase RPTPmu contains three intracellular domains: the juxtamembrane (JM) and two phosphatase domains (D1 and D2). D1 is catalytically active in vitro. The functional roles of JM and D2 are still unclear. To find out whether and how they modulate the phosphatase activity of D1, we compared the enzymatic characteristics of two constructs, containing a truncated JM and either D1 or both phosphatase domains. p-Nitrophenyl phosphate and two peptide substrates were efficiently dephosphorylated by both constructs. The specificity constant of D1 alone was up to 50% higher. D2 induces (a) decreased K(m) values for peptide substrates, (b) decreased catalytic efficiency for these substrates, (c) shifting of... (More)
The receptor-like protein tyrosine phosphatase RPTPmu contains three intracellular domains: the juxtamembrane (JM) and two phosphatase domains (D1 and D2). D1 is catalytically active in vitro. The functional roles of JM and D2 are still unclear. To find out whether and how they modulate the phosphatase activity of D1, we compared the enzymatic characteristics of two constructs, containing a truncated JM and either D1 or both phosphatase domains. p-Nitrophenyl phosphate and two peptide substrates were efficiently dephosphorylated by both constructs. The specificity constant of D1 alone was up to 50% higher. D2 induces (a) decreased K(m) values for peptide substrates, (b) decreased catalytic efficiency for these substrates, (c) shifting of the optimal pH to slightly lower values, and (d) looser binding of competitive inhibitors. These data suggest that the phosphatase activity of D1 is negatively modulated and its ligand binding capacity is sensibly modified by domain D2, having possible functional significance. (Less)
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author
publishing date
type
Contribution to journal
publication status
published
subject
keywords
intramolecular interactions, RPTPμ, protein–tyrosine phosphatase, enzyme kinetics
in
Biochemical and Biophysical Research Communications
volume
280
issue
1
pages
319 - 327
publisher
Elsevier
external identifiers
  • pmid:11162517
  • scopus:0034810733
ISSN
1090-2104
DOI
10.1006/bbrc.2000.4094
language
English
LU publication?
no
id
a0f40f9a-d79d-4216-91fe-84c543982573 (old id 1123208)
date added to LUP
2008-06-24 11:03:05
date last changed
2018-01-07 09:24:53
@article{a0f40f9a-d79d-4216-91fe-84c543982573,
  abstract     = {The receptor-like protein tyrosine phosphatase RPTPmu contains three intracellular domains: the juxtamembrane (JM) and two phosphatase domains (D1 and D2). D1 is catalytically active in vitro. The functional roles of JM and D2 are still unclear. To find out whether and how they modulate the phosphatase activity of D1, we compared the enzymatic characteristics of two constructs, containing a truncated JM and either D1 or both phosphatase domains. p-Nitrophenyl phosphate and two peptide substrates were efficiently dephosphorylated by both constructs. The specificity constant of D1 alone was up to 50% higher. D2 induces (a) decreased K(m) values for peptide substrates, (b) decreased catalytic efficiency for these substrates, (c) shifting of the optimal pH to slightly lower values, and (d) looser binding of competitive inhibitors. These data suggest that the phosphatase activity of D1 is negatively modulated and its ligand binding capacity is sensibly modified by domain D2, having possible functional significance.},
  author       = {Aricescu, Alexandru R. and Fulga, Tudor A. and Cismasiu, Valeriu and Goody, Roger S. and Szedlacsek, Stefan E.},
  issn         = {1090-2104},
  keyword      = {intramolecular interactions,RPTPμ,protein–tyrosine phosphatase,enzyme kinetics},
  language     = {eng},
  number       = {1},
  pages        = {319--327},
  publisher    = {Elsevier},
  series       = {Biochemical and Biophysical Research Communications},
  title        = {Intramolecular interactions in protein tyrosine phosphatase RPTPmu: kinetic evidence},
  url          = {http://dx.doi.org/10.1006/bbrc.2000.4094},
  volume       = {280},
  year         = {2001},
}