PTPN11 (Shp2) mutations in LEOPARD syndrome have dominant negative, not activating, effects.
Multiple lentigines/LEOPARD syndrome (LS) is a rare, autosomal dominant disorder characterized by Lentigines, Electrocardiogram abnormalities, Ocular hypertelorism, Pulmonic valvular stenosis, Abnormalities of genitalia, Retardation of growth, and Deafness. Like the more common Noonan syndrome (NS), LS is caused by germ line missense mutations in PTPN11, encoding the protein-tyrosine phosphatase Shp2. Enzymologic, structural, cell biological, and mouse genetic studies indicate that NS is caused by gain-of-function PTPN11 mutations. Because NS and LS share several features, LS has been viewed as an NS variant. We examined a panel of LS mutants, including the two most common alleles. Surprisingly, we found that in marked contrast to NS, LS mutants are catalytically defective and act as dominant negative mutations that interfere with growth factor/Erk-mitogen-activated protein kinase-mediated signaling. Molecular modeling and biochemical studies suggest that LS mutations contort the Shp2 catalytic domain and result in open, inactive forms of Shp2. Our results establish that the pathogenesis of LS and NS is distinct and suggest that these disorders should be distinguished by mutational analysis rather than clinical presentation.
Kontaridis
Maria I
MI
Cancer Biology Program, Division of Hematology-Oncology, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts 02115, USA.
Swanson
Kenneth D
KD
David
Frank S
FS
Barford
David
D
Neel
Benjamin G
BG
D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism; D020134:Catalytic Domain / Q000235:genetics; D002460:Cell Line; D020868:Gene Silencing; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D044542:LEOPARD Syndrome / Q000201:enzymology / Q000235:genetics*; D020125:Mutation, Missense; D009634:Noonan Syndrome / Q000201:enzymology / Q000235:genetics; D010750:Phosphoproteins / Q000378:metabolism; D017434:Protein Structure, Tertiary / Q000235:genetics; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D017027:Protein Tyrosine Phosphatases / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism
D048868:Adaptor Proteins, Signal Transducing; C098587:GAB1 protein, human; D047908:Intracellular Signaling Peptides and Proteins; D010750:Phosphoproteins; C516724:PTPN11 protein, human; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D017027:Protein Tyrosine Phosphatases; C516725:Ptpn11 protein, mouse