PTPN11 (Protein tyrosine phosphatase, non-receptor type, 11)

	PTPN11 genomic organization and SHP-2 domain structure: Figure 1 : (A) The PTPN11 gene and SHP-2 domain characterization. The coding exons are shown as numbered filled boxes. The functional domains of the protein, comprising two tandemly arranged SH2 domains at the N terminus (N-SH2 and C-SH2) followed by a protein tyrosine phosphatase (PTP) domain, are shown below. Numbers below the domain structure indicate the amino-acid boundaries of those domains. (B) Three-dimensional structure of SHP-2 in its catalytically inactive conformation, as determined by Hof et al. (1998). Residues involved in catalysis are shown (space fill). Figure 2 : Location of SHP-2 mutated residues in human disease. (A) Noonan syndrome and LEOPARD syndrome (germ-line origin; N=224); (B) Noonan syndrome with juvenile myelomonocytic leukemia (germ-line origin; N=11); (C) hematologic malignancies, including juvenile myelomonocytic leukemia, acute myeloid leukemia, acute lymphoblastic leukemia, myelodysplastic syndromes and chronic myelomonocytic leukemia (somatic origin; N=97). The pictures show the C trace of SHP-2 in its catalytically inactive conformation. Affected residues are indicated with their side chains as black sticks.
Description	SHP-2 is a member of a small subfamily of cytoplasmic Src homology 2 (SH2) domain-containing protein tyrosine phosphatases. Both the N-SH2 and C-SH2 domains selectively bind to short amino acid motifs containing a phosphotyrosyl residue and promote SHP-2 association with activated receptors and other signaling partners. Crystallographic data indicate that the N-SH2 domain also interacts with the PTP domain using a separate site. As these subdomains show negative cooperativity, the N-SH2 domain functions as an intramolecular switch controlling SHP-2 catalytic activation. Specifically, the N-SH2 domain interacts with the PTP domain basally, blocking the catalytic site. Binding of the N-SH2 phosphopeptide-binding site to the phosphotyrosyl ligand promotes a conformational change of the domain that weakens the auto-inhibiting intramolecular interaction, making the catalytic site available to substrate, thereby activating the phosphatase.
Expression	Widely expressed in both embryonic and adult tissues.
Localisation	Cytoplasmic. It binds to activated cell surface receptors, cell adhesion molecules and scaffolding adapters.
Function	SHP-2 functions as an intracellular signal transducer. It positively modulates signal flow in most circumstances, but can also function as negative regulator depending upon its binding partner and interactions with downstream signaling networks. SHP-2 positively controls the activation of the RAS/MAPK cascade induced by several growth factors, and negatively regulates JAK/STAT signaling. In most cases, SHP-2's function in intracellular signaling appears to be immediately proximal to activated receptors and upstream to RAS. The mechanisms of SHP-2's action and its physiological substrates are still poorly defined. However, both membrane translocation and PTPase activity are required for SHP-2 function. SHP-2 is required during development. Embryos nullizygous for Shp-2 have defects in gastrulation and mesodermal patterning resulting in severe abnormalities in axial and paraxial mesodermal structures. Shp-2 function is also required for development of terminal and skeletal structures, semilunar valvulogenesis in the heart, and hematopoiesis.
Homology	PTPN6 (protein tyrosine phosphatase, non-receptor type, 6) previously known as SHP1 or SHP-1 (Src homology 2 domain-containing protein tyrosine phosphatase, 1).

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