PI(3,4,5)P3 and PI(4,5)P2 lipids target proteins with polybasic clusters to the plasma membrane.
Many signaling, cytoskeletal, and transport proteins have to be localized to the plasma membrane (PM) in order to carry out their function. We surveyed PM-targeting mechanisms by imaging the subcellular localization of 125 fluorescent protein-conjugated Ras, Rab, Arf, and Rho proteins. Out of 48 proteins that were PM-localized, 37 contained clusters of positively charged amino acids. To test whether these polybasic clusters bind negatively charged phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] lipids, we developed a chemical phosphatase activation method to deplete PM PI(4,5)P2. Unexpectedly, proteins with polybasic clusters dissociated from the PM only when both PI(4,5)P2 and phosphatidylinositol 3,4,5-trisphosphate [PI(3,4,5)P3] were depleted, arguing that both lipid second messengers jointly regulate PM targeting.
Heo
Won Do
WD
Department of Molecular Pharmacology, 318 Campus Drive, Clark Building, Stanford University Medical School, Stanford, CA 94305, USA.
Inoue
Takanari
T
Park
Wei Sun
WS
Kim
Man Lyang
ML
Park
Byung Ouk
BO
Wandless
Thomas J
TJ
Meyer
Tobias
T
D020727:ADP-Ribosylation Factors / Q000737:chemistry / Q000378:metabolism; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D002462:Cell Membrane / Q000378:metabolism*; D020558:GTP Phosphohydrolases / Q000737:chemistry / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D007700:Kinetics; D051379:Mice; D008969:Molecular Sequence Data; D041681:NIH 3T3 Cells; D019269:Phosphatidylinositol 4,5-Diphosphate / Q000378:metabolism*; D018129:Phosphatidylinositol Phosphates / Q000378:metabolism*; D015290:Second Messenger Systems; D015398:Signal Transduction; D055672:Static Electricity; D020691:rab GTP-Binding Proteins / Q000737:chemistry / Q000378:metabolism; D018631:ras Proteins / Q000737:chemistry / Q000378:metabolism; D020741:rho GTP-Binding Proteins / Q000378:metabolism
D019269:Phosphatidylinositol 4,5-Diphosphate; D018129:Phosphatidylinositol Phosphates; C060974:phosphatidylinositol 3,4,5-triphosphate; D020558:GTP Phosphohydrolases; D020727:ADP-Ribosylation Factors; D020691:rab GTP-Binding Proteins; D018631:ras Proteins; D020741:rho GTP-Binding Proteins