ptp catalytic mechanism
DESCRIPTION
PTP catalytic mechanism. the general acid. the general base. WPD loop. D to A mutant. DA (trapping) PTPs. WT (active) PTPs. PTP1B +/+. PTP1B -/-. Background PTP1B Knock Out Mice. PTP1B -/- mice display enhanced sensitivity to insulin - PowerPoint PPT PresentationTRANSCRIPT
PTP catalytic mechanism
the general acid
the general base
WPD loop
D to A mutant
WT (active) PTPs
DA (trapping) PTPs
BackgroundPTP1B Knock Out Mice
PTP1B -/- mice display enhanced sensitivity to insulin
PTP1B -/- mice are resistant to development of obesity and Type 2 diabetes
(Elchebly et al. Science (1999) 83, 1544-1548) (Klaman et al. Mol Cell Biol (2000) 20, 5479-89)
PTP1B -/-PTP1B +/+
Inhibition of the Insulin Receptor PTP may Enhance Insulin Signaling
PTP
Prolonged or Enhanced Signal
Transient Signal
Structure of the PTP1B-IR peptide complex
R1164
pY1163 pY1162
D1161
Arg47
Arg24 Phe182
G1166
Asp48
Arg254
Tyr46
S.R. Hubbard, (1997) EMBO J., 16, 5573-5581
IRTK Activation segment: DIpY1158ETDpY1162pY1163RKGG
Kinetic Constants for Dephosphorylation of IR Activation Loop Peptide by PTP1B
RDIpY1158ETDpY1162pY1163RKGGKGLLIR-peptide
Km
[M]
pY-1158 > 100
pY-1162 > 100
pY-1163 > 100
pY-1162,1163
14 ± 1.1
pY-1158,
1162,1163 7.9 ± 1.3
Insulin
Insulin ReceptorPTK
Signaling Response
PTP1B
PTP1B and insulin signaling
Suppression of PTP1B expression by RNAi may enhance tyrosine phosphorylation of IR
PTP
Prolonged or Enhanced Signal
Transient Signal
972
1158
11621163