Conserved Protein Domain Family
PX_PLD2

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cd07297: PX_PLD2 
The phosphoinositide binding Phox Homology domain of Phospholipase D2
The PX domain is a phosphoinositide (PI) binding module present in many proteins with diverse functions such as cell signaling, vesicular trafficking, protein sorting, and lipid modification, among others. Phospholipase D (PLD) catalyzes the hydrolysis of the phosphodiester bond of phosphatidylcholine to generate membrane-bound phosphatidic acid and choline. PLD activity has been detected in viruses, bacteria, yeast, plants, and mammals, but the PX domain is not present in PLDs from viruses and bacteria. PLDs are implicated in many cellular functions like signaling, cytoskeletal reorganization, vesicular transport, stress responses, and the control of differentiation, proliferation, and survival. PLD2 contains PX and Pleckstrin Homology (PH) domains in addition to the catalytic domain. It mediates EGF-dependent insulin secretion and EGF-induced Ras activation by the guanine nucleotide-exchange factor Son of sevenless (Sos). It regulates mast cell activation by associating and promoting the activation of the protein tyrosine kinase Syk. PLD2 also participates in the sphingosine 1-phosphate-mediated pathway that stimulates the migration of endothelial cells, an important factor in angiogenesis. The PX domain is involved in targeting of proteins to PI-enriched membranes, and may also be involved in protein-protein interaction.
Statistics
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PSSM-Id: 132830
View PSSM: cd07297
Aligned: 3 rows
Threshold Bit Score: 247.909
Threshold Setting Gi: 189519213
Created: 23-Feb-2009
Updated: 17-Jan-2013
Structure
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Aligned Rows:
 
phosphoinosit..
Feature 1:phosphoinositide binding site [chemical binding site]
Evidence:
  • Comment:A majority of PX domain containing proteins binds phosphatidylinositol-3-phosphate (PI3P) at this site. In some cases, other phosphoinositides, such as PI4P or PI(3,4)P2, are the preferred substrates.
  • 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 8247945    62 GVPVIAQVVGTERYTsgsKVGTCTLYSVRLTHGDFTWTTKKKFRHFQELHRDLQRHKVLMSLLnlarfaaah--sparea 139
gi 189519213  56 GTPITCKVENTERYTtrsKVHVCTLYTVRLTHGEFTWTVKRKYKHFQELHRDLYKHKVMLQFLplgrfaiq---rqqlag 132
gi 213982959  63 GVPVTARVSDTERYTrgtKVRHSTLYTIILTHGPFTWTIKKKFKHFQELHRDLLRHKLFISFLpfnplsrfhvtrsrvet 142
                         90       100       110       120       130
                 ....*....|....*....|....*....|....*....|....*....|...
Feature 1                 ##           #                              
gi 8247945   140 anENIPSLPRGGSegsaRHTASKQKYLENYLNRLLTMSFYRNYHAMTEFLEVS 192
gi 189519213 133 ltEEMPTLHGTDRi---RRTSSKPKYLEEYLNNLLENTFYKNYHGMMDFLAIS 182
gi 213982959 143 tsSEMPSLPHASGea-sQRMASKKAYLNNYLNVLLGKSFYRNYHAMREFLDVS 194

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