Conserved Protein Domain Family
PX_PI3K_C2_68D

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cd06884: PX_PI3K_C2_68D 
The phosphoinositide binding Phox Homology Domain of Class II Phosphoinositide 3-Kinases similar to the Drosophila PI3K_68D protein
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. 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. PI3K_68D is a novel PI3K which is widely expressed throughout the Drosophila life cycle. In vitro, it has been shown to phosphorylate PI and PI4P. It is involved in signaling pathways that affect pattern formation of Drosophila wings.
Statistics
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PSSM-Id: 132794
View PSSM: cd06884
Aligned: 6 rows
Threshold Bit Score: 188.781
Threshold Setting Gi: 215496736
Created: 14-Jul-2008
Updated: 17-Jan-2013
Structure
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Aligned Rows:
 
putative
Feature 1:putative 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:
                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
Feature 1                                               ###                        ##             
gi 2113838   1611 LKIVKVVCFQKHYsmeKFYMYILEVTRHGqpdPTHLFRSYREFTEFHQKLCMHFPl-VKLHSLPAGVHVGRsNIKSVAEK 1689
gi 170573884 1269 ITRVDVLAFEKWHipeKVYMYKVEVNRENeavCGIVYRSFVEFNELYIKLCRRFPf-AHLPPLSQGTNVGRsNIRKVAER 1347
gi 193716060 1411 IVRVEVYGCQKRYdpeKYYVYILKVFRENqrdPSYLFRSYKELSEFQQKLLLLFPlaKFLSLLNTSIHMGRsHIKQVAEK 1490
gi 189241618 1281 LVHVQVVSYKKRYdpdKYYVYVLRVTREGdksDMEIHRTYKEFCELHQKLCIYFPl-AKLHSLTTGLHVGRsNIKQVAEK 1359
gi 215507904 1370 IVSLTVTGCHKRYepeKHYTYSVKITRESqtsSIHVFRTYAEFLELYQKLVRMFPl-AKFYPLSKGSFVGRsNTREVAER 1448
gi 215496736 1017 IVQLTVEDIRLRYhpeRYYVYVVNVEREFp-pAQSVIRTYKNFLELYTKMSRKFPa-CDFHPLSRGSVFSSeGDESLALK 1094
                          90       100       110
                  ....*....|....*....|....*....|..
Feature 1         #                               
gi 2113838   1690 RLPLIQRFLKSLFDAseEIAHSELVYTFFHPL 1721
gi 170573884 1348 RQADLQQFLNVLFEYhpEVASSDLVYTFFHII 1379
gi 193716060 1491 RRVEIQNFLNTLFQMapEVSHSDLVYTFFHPL 1522
gi 189241618 1360 RYQEVSSFITSLFKCadEIAHSDLVYTFFHPL 1391
gi 215507904 1449 RKQDVEAFLLSLKKMaeEVSHCSLIYTFFHPL 1480
gi 215496736 1095 RKRDIQQFLDTVMAQpeDVSHYRLVYSFFHPL 1126

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