Regulation of phospholipase D activity, membrane targeting and intracellular trafficking by phosphoinositides

2007 ◽  
Vol 74 (1) ◽  
pp. 247 ◽  
Author(s):  
Andrew J. Morris
Keyword(s):  
Phospholipase D ◽  
Intracellular Trafficking ◽  
Membrane Targeting

Regulation of phospholipase D activity, membrane targeting and intracellular trafficking by phosphoinositides

2007 ◽  
Vol 74 ◽  
pp. 247-257 ◽  
Author(s):  
Andrew J. Morris
Keyword(s):  
Phospholipase D ◽  
Intracellular Trafficking ◽  
Endocytic Pathway ◽  
Signalling Pathways ◽  
Membrane Targeting ◽  
Phosphoinositide Metabolism ◽  
Binding Studies ◽  
Catalytic Core ◽  
Stimulation Of

Generation of PA (phosphatidic acid) by PLD (phospholipase D)-catalysed hydrolysis of phosphatidylcholine plays a pivotal role in cellular signalling pathways that regulate organization of the actin cytoskeleton, vesicular transport and exocytosis and stimulation of cell growth and survival. PLD regulation and function are intimately linked with phosphoinositide metabolism. Phosphatidyl 4-phosphate 5-kinase is stimulated by PA in vitro and this enzyme is the downstream effector of a significant subset of PLD signalling pathways. Yeast and mammalian PLDs are potently and specifically activated by the product of this kinase, PtdIns(4,5)P2, through interactions mediated by a polybasic motif within the catalytic core of the enzyme. Integrity of this motif is critical for agonist activation of mammalian PLD and for PLD function in secretion, sporulation and exocytosis in vivo. Although dispensable for catalysis in vitro, these PLD enzymes also contain N-terminal PH (pleckstrin) and PX (phox) homology domains. Binding studies using recombinantly expressed PLD fragments indicate that the PH and PX domains also interact specifically with distinct phosphoinositide ligands. Both the PX and PH domains are important for PLD function by controlling the dynamic association of the enzyme with the plasma membrane and its intracellular trafficking by the endocytic pathway. These results identify two distinct modes of regulation of PLD by phosphoinositides: stimulation of catalysis mediated by the polybasic domain and dynamic regulation of membrane targeting mediated primarily by the PH and PX domains.

scholarly journals Intracellular Trafficking and Membrane Targeting Mechanisms of the Human Reduced Folate Carrier in Mammalian Epithelial Cells

2002 ◽  
Vol 277 (36) ◽  
pp. 33325-33333 ◽  
Author(s):  
Jonathan S. Marchant ◽  
Veedamali S. Subramanian ◽  
Ian Parker ◽  
Hamid M. Said
Keyword(s):  
Epithelial Cells ◽  
Intracellular Trafficking ◽  
Membrane Targeting ◽  
Reduced Folate Carrier

scholarly journals Amino-terminal Cysteine Residues Differentially Influence RGS4 Protein Plasma Membrane Targeting, Intracellular Trafficking, and Function

2012 ◽  
Vol 287 (34) ◽  
pp. 28966-28974 ◽  
Author(s):  
Guillaume Bastin ◽  
Kevin Singh ◽  
Kaveesh Dissanayake ◽  
Alexandra S. Mighiu ◽  
Aliya Nurmohamed ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Intracellular Trafficking ◽  
Cysteine Residues ◽  
Membrane Targeting ◽  
Amino Terminal ◽  
And Function

Intracellular trafficking/membrane targeting of human reduced folate carrier expressed in Xenopus oocytes

2001 ◽  
Vol 281 (6) ◽  
pp. G1477-G1486 ◽  
Author(s):  
Veedamali S. Subramanian ◽  
Jonathan S. Marchant ◽  
Ian Parker ◽  
Hamid M. Said
Keyword(s):  
Plasma Membrane ◽  
Intracellular Trafficking ◽  
Fluorescent Protein ◽  
Cytoplasmic Tail ◽  
Confocal Imaging ◽  
Membrane Targeting ◽  
Reduced Folate Carrier ◽  
Animal Pole ◽  
Molecular Determinant ◽  
Green Fluorescent

The major cellular pathway for uptake of the vitamin folic acid, including its absorption in the intestine, is via a plasma membrane carrier system, the reduced folate carrier (RFC). Very little is known about the mechanisms that control intracellular trafficking and plasma membrane targeting of RFC. To begin addressing these issues, we used Xenopus oocyte as a model system and examined whether the signal that targets the protein to the plasma membrane is located in the COOH-terminal cytoplasmic tail or in the backbone of the polypeptide. We also examined the role of microtubules and microfilaments in intracellular trafficking of the protein. Confocal imaging of human RFC (hRFC) fused to the enhanced green fluorescent protein (hRFC-EGFP) showed that the protein was expressed at the plasma membrane, with expression confined almost entirely to the animal pole of the oocyte. Localization of hRFC at the plasma membrane was not affected by partial or total truncation of the COOH-terminal tail of the polypeptide, whereas a construct of the cytoplasmic tail fused to EGFP was not found at the plasma membrane. Disruption of microtubules, but not microfilaments, prevented hRFC expression at the plasma membrane. These results demonstrate that the molecular determinant(s) that directs plasma membrane targeting of hRFC is located within the backbone of the polypeptide and that intact microtubules, but not microfilaments, are essential for intracellular trafficking of the protein.

Sign in / Sign up

Export Citation Format

Share Document