Crystal Structure of FLT3
[FLT3_HUMAN] Defects in FLT3 are a cause of acute myelogenous leukemia (AML) [MIM:601626]. AML is a malignant disease in which hematopoietic precursors are arrested in an early stage of development. Note=Somatic mutations that lead to constitutive activation of FLT3 are frequent in AML patients. These mutations fall into two classes, the most common being in-frame internal tandem duplications of variable length in the juxtamembrane region that disrupt the normal regulation of the kinase activity. Likewise, point mutations in the activation loop of the kinase domain can result in a constitutively activated kinase.       
[FLT3_HUMAN] Tyrosine-protein kinase that acts as cell-surface receptor for the cytokine FLT3LG and regulates differentiation, proliferation and survival of hematopoietic progenitor cells and of dendritic cells. Promotes phosphorylation of SHC1 and AKT1, and activation of the downstream effector MTOR. Promotes activation of RAS signaling and phosphorylation of downstream kinases, including MAPK1/ERK2 and/or MAPK3/ERK1. Promotes phosphorylation of FES, FER, PTPN6/SHP, PTPN11/SHP-2, PLCG1, and STAT5A and/or STAT5B. Activation of wild-type FLT3 causes only marginal activation of STAT5A or STAT5B. Mutations that cause constitutive kinase activity promote cell proliferation and resistance to apoptosis via the activation of multiple signaling pathways.          
Publication Abstract from PubMed
FLT3 is a type III receptor tyrosine kinase that is thought to play a key role in hematopoiesis. Certain classes of FLT3 mutations cause constitutively activated forms of the receptor that are found in significant numbers of patients with acute myelogenous leukemia (AML). The mutations occur either in the activation loop, for example, as point mutations of Asp835 or as internal tandem duplication (ITD) sequences in the juxtamembrane (JM) domain. To further understand the nature of FLT3 autoinhibition and regulation, we have determined the crystal structure of the autoinhibited form of FLT3. This structure shows the autoinhibitory conformation of a complete JM domain in this class of receptor tyrosine kinases. The detailed inhibitory mechanism of the JM domain is revealed, which is likely utilized by other members of type III receptor tyrosine kinases.
The structural basis for autoinhibition of FLT3 by the juxtamembrane domain.,Griffith J, Black J, Faerman C, Swenson L, Wynn M, Lu F, Lippke J, Saxena K Mol Cell. 2004 Jan 30;13(2):169-78. PMID:14759363
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.