View source for 8gub


==Cryo-EM structure of cancer-specific PI3Kalpha mutant H1047R in complex with BYL-719==
<StructureSection load='8gub' size='340' side='right'caption='[[8gub]], [[Resolution|resolution]] 2.73&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[8gub]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=8GUB OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=8GUB FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Electron Microscopy, [[Resolution|Resolution]] 2.73&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=1LT:(2S)-N~1~-{4-METHYL-5-[2-(1,1,1-TRIFLUORO-2-METHYLPROPAN-2-YL)PYRIDIN-4-YL]-1,3-THIAZOL-2-YL}PYRROLIDINE-1,2-DICARBOXAMIDE'>1LT</scene></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=8gub FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=8gub OCA], [https://pdbe.org/8gub PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=8gub RCSB], [https://www.ebi.ac.uk/pdbsum/8gub PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=8gub ProSAT]</span></td></tr>
</table>
== Disease ==
[https://www.uniprot.org/uniprot/PK3CA_HUMAN PK3CA_HUMAN] Note=Most of the cancer-derived mutations are missense mutations and map to one of the three hotspots: Glu-542; Glu-545 and His-1047. Mutated isoforms participate in cellular transformation and tumorigenesis induced by oncogenic receptor tyrosine kinases (RTKs) and HRAS1/KRAS. Interaction with HRAS1/KRAS is required for Ras-driven tumor formation. Mutations increasing the lipid kinase activity are required for oncogenic signaling. The protein kinase activity may not be required for tumorigenesis.  Defects in PIK3CA are associated with colorectal cancer (CRC) [MIM:[https://omim.org/entry/114500 114500].  Defects in PIK3CA are a cause of susceptibility to breast cancer (BC) [MIM:[https://omim.org/entry/114480 114480]. A common malignancy originating from breast epithelial tissue. Breast neoplasms can be distinguished by their histologic pattern. Invasive ductal carcinoma is by far the most common type. Breast cancer is etiologically and genetically heterogeneous. Important genetic factors have been indicated by familial occurrence and bilateral involvement. Mutations at more than one locus can be involved in different families or even in the same case.  Defects in PIK3CA are a cause of susceptibility to ovarian cancer (OC) [MIM:[https://omim.org/entry/167000 167000]. Ovarian cancer common malignancy originating from ovarian tissue. Although many histologic types of ovarian neoplasms have been described, epithelial ovarian carcinoma is the most common form. Ovarian cancers are often asymptomatic and the recognized signs and symptoms, even of late-stage disease, are vague. Consequently, most patients are diagnosed with advanced disease.  Defects in PIK3CA may underlie hepatocellular carcinoma (HCC) [MIM:[https://omim.org/entry/114550 114550].<ref>PMID:15608678</ref>   Defects in PIK3CA are a cause of keratosis seborrheic (KERSEB) [MIM:[https://omim.org/entry/182000 182000]. A common benign skin tumor. Seborrheic keratoses usually begin with the appearance of one or more sharply defined, light brown, flat macules. The lesions may be sparse or numerous. As they initially grow, they develop a velvety to finely verrucous surface, followed by an uneven warty surface with multiple plugged follicles and a dull or lackluster appearance.<ref>PMID:17673550</ref>   Defects in PIK3CA are the cause of congenital lipomatous overgrowth, vascular malformations, and epidermal nevi (CLOVE) [MIM:[https://omim.org/entry/612918 612918]. CLOVE is a sporadically occurring, non-hereditary disorder characterized by asymmetric somatic hypertrophy and anomalies in multiple organs. It is defined by four main clinical findings: congenital lipomatous overgrowth, vascular malformations, epidermal nevi, and skeletal/spinal abnormalities. The presence of truncal overgrowth and characteristic patterned macrodactyly at birth differentiates CLOVE from other syndromic forms of overgrowth.<ref>PMID:22658544</ref> 
== Function ==
[https://www.uniprot.org/uniprot/PK3CA_HUMAN PK3CA_HUMAN] Phosphoinositide-3-kinase (PI3K) that phosphorylates PtdIns (Phosphatidylinositol), PtdIns4P (Phosphatidylinositol 4-phosphate) and PtdIns(4,5)P2 (Phosphatidylinositol 4,5-bisphosphate) to generate phosphatidylinositol 3,4,5-trisphosphate (PIP3). PIP3 plays a key role by recruiting PH domain-containing proteins to the membrane, including AKT1 and PDPK1, activating signaling cascades involved in cell growth, survival, proliferation, motility and morphology. Participates in cellular signaling in response to various growth factors. Involved in the activation of AKT1 upon stimulation by receptor tyrosine kinases ligands such as EGF, insulin, IGF1, VEGFA and PDGF. Involved in signaling via insulin-receptor substrate (IRS) proteins. Essential in endothelial cell migration during vascular development through VEGFA signaling, possibly by regulating RhoA activity. Required for lymphatic vasculature development, possibly by binding to RAS and by activation by EGF and FGF2, but not by PDGF. Regulates invadopodia formation in breast cancer cells through the PDPK1-AKT1 pathway. Participates in cardiomyogenesis in embryonic stem cells through a AKT1 pathway. Participates in vasculogenesis in embryonic stem cells through PDK1 and protein kinase C pathway. Has also serine-protein kinase activity: phosphorylates PIK3R1 (p85alpha regulatory subunit), EIF4EBP1 and HRAS.<ref>PMID:21708979</ref> 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Phosphoinositide 3-kinases (PI3Ks) are a family of lipid kinases that perform multiple and important cellular functions. The protein investigated here belongs to class IA of the PI3Ks; it is a dimer consisting of a catalytic subunit, p110alpha, and a regulatory subunit, p85alpha, and is referred to as PI3Kalpha. The catalytic subunit p110alpha is frequently mutated in cancer. The mutations induce a gain of function and constitute a driving force in cancer development. About 80% of these mutations lead to single-amino-acid substitutions in one of three sites of p110alpha: two in the helical domain of the protein (E542K and E545K) and one at the C-terminus of the kinase domain (H1047R). Here, we report the cryo-electron microscopy structures of these mutants in complex with the p110alpha-specific inhibitor BYL-719. The H1047R mutant rotates its sidechain to a new position and weakens the kalpha11 activation loop interaction, thereby reducing the inhibitory effect of p85alpha on p110alpha. E542K and E545K completely abolish the tight interaction between the helical domain of p110alpha and the N-terminal SH2 domain of p85alpha and lead to the disruption of all p85alpha binding and a dramatic increase in flexibility of the adaptor-binding domain (ABD) in p110alpha. Yet, the dimerization of PI3Kalpha is preserved through the ABD-p85alpha interaction. The local and global structural features induced by these mutations provide molecular insights into the activation of PI3Kalpha, deepen our understanding of the oncogenic mechanism of this important signaling molecule, and may facilitate the development of mutant-specific inhibitors.

Cryo-EM structures of cancer-specific helical and kinase domain mutations of PI3Kalpha.,Liu X, Zhou Q, Hart JR, Xu Y, Yang S, Yang D, Vogt PK, Wang MW Proc Natl Acad Sci U S A. 2022 Nov 16;119(46):e2215621119. doi: , 10.1073/pnas.2215621119. Epub 2022 Nov 7. PMID:36343266<ref>PMID:36343266</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 8gub" style="background-color:#fffaf0;"></div>

==See Also==
*[[Phosphoinositide 3-kinase 3D structures|Phosphoinositide 3-kinase 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Homo sapiens]]
[[Category: Large Structures]]
[[Category: Hart JR]]
[[Category: Liu X]]
[[Category: Vogt PK]]
[[Category: Wang M-W]]
[[Category: Xu Y]]
[[Category: Yang D]]
[[Category: Yang S]]
[[Category: Zhou Q]]