2AR5,2IWL


Conserved Protein Domain Family
PX_PI3K_C2

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cd06883: PX_PI3K_C2 
Click on image for an interactive view with Cn3D
The phosphoinositide binding Phox Homology Domain of Class II Phosphoinositide 3-Kinases
The PX domain is a phosphoinositide (PI) binding module present in many proteins with diverse functions. The Phosphoinositide 3-Kinase (PI3K) family of enzymes catalyzes the phosphorylation of the 3-hydroxyl group of the inositol ring of phosphatidylinositol. PI3Ks play an important role in a variety of fundamental cellular processes, including cell motility, the Ras pathway, vesicle trafficking and secretion, immune cell activation and apoptosis. They are also involved in the regulation of clathrin-mediated membrane trafficking as well as ATP-dependent priming of neurosecretory granule exocytosis. PI3Ks are divided into three main classes (I, II, and III) based on their substrate specificity, regulation, and domain structure. Class II PI3Ks preferentially use PI as a substrate to produce PI3P, but can also phosphorylate PI4P to produce PI(3,4)P2. They function as monomers and do not associate with any regulatory subunits. Class II enzymes contain an N-terminal Ras binding domain, a lipid binding C2 domain, a PI3K homology domain of unknown function, an ATP-binding cataytic domain, a PX domain, and a second C2 domain at the C-terminus. Class II PI3Ks include three vertebrate isoforms (alpha, beta, and gamma), the Drosophila PI3K_68D, and similar proteins.
Statistics
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PSSM-Id: 132793
View PSSM: cd06883
Aligned: 9 rows
Threshold Bit Score: 147.118
Threshold Setting Gi: 13632586
Created: 14-Jul-2008
Updated: 2-Oct-2020
Structure
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Program:
Drawing:
Aligned Rows:
 
phosphoinosit..
Conserved site includes 6 residues -Click on image for an interactive view with Cn3D
Feature 1:phosphoinositide binding site [chemical binding site]
Evidence:
  • Comment:The PX domain of PI3K-C2alpha preferentially binds phosphatidylinositol-4,5-bisphosphate (PI(4,5)P2).
  • Comment:based on the structures of phosphatidylinositol-3-phosphate bound to other members of this superfamily
  • Comment:Two basic residues are key in binding with phosphoinositides: one forms hydrogen bonds with the 3-phosphate of PI(3)P and another forms hydrogen bonds with the 4-and 5-hydroxyl groups of PI(3)P.

Sequence Alignment
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Format: Row Display: Color Bits: Type Selection:
Feature 1                                               ###                       ##             #
2AR5_A          7 EVSVFTYHKKynpdKHYIYVVRILRegq--iePSFVFRTFDEFQELHNKLSIIFPlwKLPGFPNRMVLGRthikDVAAKR 84   human
2IWL_X         22 EVSVFTYHKKynpdKHYIYVVRILRegq--iePSFVFRTFDEFQELHNKLSIIFPlwKLPGFPNRMVLGRthikDVAAKR 99   human
O00750       1369 DVFLCRHEKIfhpnKGYIYVVKVMRent--heATYIQRTFEEFQELHNKLRLLFPssHLPSFPSRFVIGRsrgeAVAERR 1446 human
XP_002234890 1023 SLSVFGFQKRysgeKYYVYIIKVYRqdr--eePTFVFRTYDELFELHQRLTLAFPhnRLPSFPTRTVIGRsnikQVAERR 1100 Florida lancelet
XP_001638040 1050 SARVVDYQKRynteKYYIYVINICRans--dqATFVFRRFGHFIELHAKLSELYPdiALPRLPARIYLGRsqirTVAERR 1127 starlet sea a...
CAA63485     1613 IVKVVCFQKHysmeKFYMYILEVTRhgq--pdPTHLFRSYREFTEFHQKLCMHFPlvKLHSLPAGVHVGRsnikSVAEKR 1690 fruit fly
O75747       1206 ERAILGFSKK----SSNLYLIQVTHsn---neTSLTEKSFEQFSKLHSQLQKQFAslTLPEFPHWWHLPFt---NSDHRR 1275 human
XP_002122780 1509 MATVVGYQKRyspgKYYMFCVKVTRekntttkDSYVFRTFSEFEELHRKLSFVYPs-KLPSFSDSVVVGRsqvkQVAERR 1587 Ciona intesti...
XP_001193595  248 EAKVFGIQKRyeteKYYVYIVRLLRags--tvPLFIFRRYSEFGELRDKLGLLYPtfGLPPLLSHRRVGRthvkQVAERR 325  purple urchin
Feature 1                                        
2AR5_A         85 KIELNSYLQSLMNAstDVAECDLVCTFFHGS 115  human
2IWL_X        100 KIELNSYLQSLMNAstDVAECDLVCTFFHPL 130  human
O00750       1447 REELNGYIWHLIHAppEVAECDLVYTFFHPL 1477 human
XP_002234890 1101 QVDLNIYLKEVMSAppQVSQSDLVYTFFHPM 1131 Florida lancelet
XP_001638040 1128 RAELDTFLRHLLMMpqEISESDVLYTFLHPI 1158 starlet sea anemone
CAA63485     1691 LPLIQRFLKSLFDAseEIAHSELVYTFFHPL 1721 fruit fly
O75747       1276 FRDLNHYMEQILNVshEVTNSDCVLSFFLSE 1306 human
XP_002122780 1588 KIKLNSYLSFLFKSqkTIAMHDLVYTFFHPI 1618 Ciona intestinalis
XP_001193595  326 KKELERYLRWLFSMppEVSQCDLVYTFFHPS 356  purple urchin

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