Phospholipase D1 and potential targets of its hydrolysis product, phosphatidic acid

2003 ◽  
Vol 31 (1) ◽  
pp. 94-97 ◽  
Author(s):  
N.T. Ktistakis ◽  
C. Delon ◽  
M. Manifava ◽  
E. Wood ◽  
I. Ganley ◽  
...  
Keyword(s):  
Phosphatidic Acid ◽  
Hydrolysis Product ◽  
Ph Domain ◽  
Novel Proteins ◽  
Fatty Acylation ◽  
Px Domain ◽  
Phospholipase D1 ◽  
Sphingosine 1 Phosphate ◽  
Phox Homology ◽  
Adp Ribosylation Factor

Phospholipase D (PLD) hydrolyses phosphatidylcholine into phosphatidic acid (PA) and choline. Our work aims to understand the properties of PLD1, and to identify downstream targets of PA. In one set of projects, we have focused on membrane-targeting mechanisms and have proposed a hierarchy of signals that allows PLD1 to localize to intracellular membranes. These signals involve a functional pleckstrin homology (PH) domain and its fatty acylation on two adjacent cysteine residues. A nearby Phox homology (PX) domain may modulate the function of the fatty acylated PH domain. This complex array of signals is probably necessitated by the targeting of PLD1 to multiple endocytic and secretory membranes under basal and signal-dependent conditions. In another set of projects, we have used chemically synthesized PA coupled to a solid support in order to identify proteins that interact with this phospholipid. Several proteins have emerged from this screen as potential targets. Some (e.g. ADP-ribosylation factor, coatomer β subunit) are involved in trafficking and their PA affinity can be understood in terms of their regulated cycling on and off membranes during rounds of transport. Others (sphingosine 1-phosphate kinase and PtdIns4P 5-kinase) are implicated in pathways that also involve PLD activation. Others still are novel proteins (brain-specific neurochondrin) whose affinity for PA may contribute to an understanding of their cellular function.

scholarly journals Regulation of phospholipase D1 subcellular cycling through coordination of multiple membrane association motifs

2003 ◽  
Vol 162 (2) ◽  
pp. 305-315 ◽  
Author(s):  
Guangwei Du ◽  
Yelena M. Altshuller ◽  
Nicolas Vitale ◽  
Ping Huang ◽  
Sylvette Chasserot-Golaz ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Membrane Vesicle ◽  
Membrane Association ◽  
Ph Domain ◽  
Px Domain ◽  
Ph Domains ◽  
Phospholipase D1 ◽  
And Function ◽  
Phox Homology ◽  
Cellular Stimulation

The signaling enzyme phospholipase D1 (PLD1) facilitates membrane vesicle trafficking. Here, we explore how PLD1 subcellular localization is regulated via Phox homology (PX) and pleckstrin homology (PH) domains and a PI4,5P2-binding site critical for its activation. PLD1 localized to perinuclear endosomes and Golgi in COS-7 cells, but on cellular stimulation, translocated to the plasma membrane in an activity-facilitated manner and then returned to the endosomes. The PI4,5P2-interacting site sufficed to mediate outward translocation and association with the plasma membrane. However, in the absence of PX and PH domains, PLD1 was unable to return efficiently to the endosomes. The PX and PH domains appear to facilitate internalization at different steps. The PH domain drives PLD1 entry into lipid rafts, which we show to be a step critical for internalization. In contrast, the PX domain appears to mediate binding to PI5P, a lipid newly recognized to accumulate in endocytosing vesicles. Finally, we show that the PH domain–dependent translocation step, but not the PX domain, is required for PLD1 to function in regulated exocytosis in PC12 cells. We propose that PLD1 localization and function involves regulated and continual cycling through a succession of subcellular sites, mediated by successive combinations of membrane association interactions.

Phospholipase D1 and Potential Targets of Its Hydrolysis Product, Phosphatidic Acid

ChemInform ◽  
2003 ◽  
Vol 34 (28) ◽  
Author(s):  
N. T. Ktistakis ◽  
C. Delon ◽  
M. Manifava ◽  
E. Wood ◽  
I. Ganley ◽  
...  
Keyword(s):  
Phosphatidic Acid ◽  
Hydrolysis Product ◽  
Phospholipase D1

The Phox homology (PX) domain, a new player in phosphoinositide signalling

2001 ◽  
Vol 360 (3) ◽  
pp. 513-530 ◽  
Author(s):  
Yue XU ◽  
Li-Fong SEET ◽  
Brendon HANSON ◽  
Wanjin HONG
Keyword(s):  
Ph Domain ◽  
Pleckstrin Homology ◽  
Structural Motifs ◽  
Cellular Processes ◽  
Enth Domain ◽  
Fyve Domain ◽  
Cellular Events ◽  
Px Domain ◽  
Phox Homology ◽  
Recent Establishment

Phosphoinositides are key regulators of diverse cellular processes. The pleckstrin homology (PH) domain mediates the action of PtdIns(3,4)P2, PtdIns(4,5)P2 and PtdIns(3,4,5)P3, while the FYVE domain relays the pulse of PtdIns3P. The recent establishment that the Phox homology (PX) domain interacts with PtdIns3P and other phosphoinositides suggests another mechanism by which phosphoinositides can regulate/integrate multiple cellular events via a spectrum of PX domain-containing proteins. Together with the recent discovery that the epsin N-terminal homologue (ENTH) domain interacts with PtdIns(4,5)P2, it is becoming clear that phosphoinositides regulate diverse cellular events through interactions with several distinct structural motifs present in many different proteins.

scholarly journals Pleckstrin homology (PH) domains and phosphoinositides

2007 ◽  
Vol 74 ◽  
pp. 81-93 ◽  
Author(s):  
Mark A. Lemmon
Keyword(s):  
Ph Domain ◽  
Pleckstrin Homology ◽  
High Affinity ◽  
Weak Binding ◽  
Ph Domains ◽  
Common Domain ◽  
Functional Relevance ◽  
Phox Homology ◽  
Adp Ribosylation Factor ◽  
Homology Domains

PH (pleckstrin homology) domains represent the 11th most common domain in the human proteome. They are best known for their ability to bind phosphoinositides with high affinity and specificity, although it is now clear that less than 10% of all PH domains share this property. Cases in which PH domains bind specific phosphoinositides with high affinity are restricted to those phosphoinositides that have a pair of adjacent phosphates in their inositol headgroup. Those that do not [PtdIns3P, PtdIns5P and PtdIns(3,5)P2] are instead recognized by distinct classes of domains including FYVE domains, PX (phox homology) domains, PHD (plant homeodomain) fingers and the recently identified PROPPINs (b-propellers that bind polyphosphoinositides). Of the 90% of PH domains that do not bind strongly and specifically to phosphoinositides, few are well understood. One group of PH domains appears to bind both phosphoinositides (with little specificity) and Arf (ADP-ribosylation factor) family small G-proteins, and are targeted to the Golgi apparatus where both phosphoinositides and the relevant Arfs are both present. Here, the PH domains may function as coincidence detectors. A central challenge in understanding the majority of PH domains is to establish whether the very low affinity phosphoinositide binding reported in many cases has any functional relevance. For PH domains from dynamin and from Dbl family proteins, this weak binding does appear to be functionally important, although its precise mechanistic role is unclear. In many other cases, it is quite likely that alternative binding partners are more relevant, and that the observed PH domain homology represents conservation of structural fold rather than function.

scholarly journals Regulation of cytokine-independent survival kinase (CISK) by the Phox homology domain and phosphoinositides

2001 ◽  
Vol 154 (4) ◽  
pp. 699-706 ◽  
Author(s):  
Jun Xu ◽  
Dan Liu ◽  
Gordon Gill ◽  
Zhou Songyang
Keyword(s):  
Membrane Trafficking ◽  
Direct Interaction ◽  
Lipid Binding ◽  
Ph Domain ◽  
Growth And Survival ◽  
Binding Domains ◽  
Px Domain ◽  
And Function ◽  
Phox Homology

PKB/Akt and serum and glucocorticoid–regulated kinase (SGK) family kinases are important downstream targets of phosphatidylinositol 3 (PI-3) kinase and have been shown to mediate a variety of cellular processes, including cell growth and survival. Although regulation of Akt can be achieved through several mechanisms, including its phosphoinositide-binding Pleckstrin homology (PH) domain, how SGK kinases are targeted and regulated remains to be elucidated. Unlike Akt, cytokine-independent survival kinase (CISK)/SGK3 contains a Phox homology (PX) domain. PX domains have been implicated in several cellular events involving membrane trafficking. However, their precise function remains unknown. We demonstrate here that the PX domain of CISK interacts with phosphatidylinositol (PtdIns)(3,5)P2, PtdIns(3,4,5)P3, and to a lesser extent PtdIns(4,5)P2. The CISK PX domain is required for targeting CISK to the endosomal compartment. Mutation in the PX domain that abolished its phospholipid binding ability not only disrupted CISK localization, but also resulted in a decrease in CISK activity in vivo. These results suggest that the PX domain regulates CISK localization and function through its direct interaction with phosphoinositides. Therefore, CISK and Akt have evolved to utilize different lipid binding domains to accomplish a similar mechanism of activation in response to PI-3 kinase signaling.

scholarly journals Determinants of the Endosomal Localization of Sorting Nexin 1

2005 ◽  
Vol 16 (4) ◽  
pp. 2049-2057 ◽  
Author(s):  
Qi Zhong ◽  
Martin J. Watson ◽  
Cheri S. Lazar ◽  
Andrea M. Hounslow ◽  
Jonathan P. Waltho ◽  
...  
Keyword(s):  
Binding Pocket ◽  
Early Endosome ◽  
Nmr Structure ◽  
Sorting Nexin ◽  
High Affinity ◽  
Terminal Domain ◽  
Px Domain ◽  
Phox Homology ◽  
Phosphatidylinositol 3

The sorting nexin (SNX) family of proteins is characterized by sequence-related phox homology (PX) domains. A minority of PX domains bind with high affinity to phosphatidylinositol 3-phosphate [PI(3)P], whereas the majority of PX domains exhibit low affinity that is insufficient to target them to vesicles. SNX1 is located on endosomes, but its low affinity PX domain fails to localize in vivo. The NMR structure of the PX domain of SNX1 reveals an overall fold that is similar to high-affinity PX domains. However, the phosphatidylinositol (PI) binding pocket of the SNX1 PX domain is incomplete; regions of the pocket that are well defined in high-affinity PX domains are highly mobile in SNX1. Some of this mobility is lost upon binding PI(3)P. The C-terminal domain of SNX1 is a long helical dimer that localizes to vesicles but not to the early endosome antigen-1–containing vesicles where endogenous SNX1 resides. Thus, the obligate dimerization of SNX1 that is driven by the C-terminal domain creates a high-affinity PI binding species that properly targets the holo protein to endosomes.

Growth Factors Mobilize Multiple Pools of KCa Channels in Developing Parasympathetic Neurons: Role of ADP-Ribosylation Factors and Related Proteins

2005 ◽  
Vol 94 (2) ◽  
pp. 1597-1605 ◽  
Author(s):  
Kwon-Seok Chae ◽  
Kwang-Seok Oh ◽  
Stuart E. Dryer
Keyword(s):  
Plasma Membrane ◽  
Growth Factors ◽  
Golgi Apparatus ◽  
Bound States ◽  
Brefeldin A ◽  
Dominant Negative ◽  
Over Expression ◽  
Adp Ribosylation ◽  
Phospholipase D1 ◽  
Adp Ribosylation Factor

In developing ciliary ganglion (CG) neurons, movement of functional large-conductance (BK type) Ca2+-activated K+ ( KCa) channels to the cell surface is stimulated by the endogenous growth factors TGFβ1 and β-neuregulin-1 (NRG1). Here we show that a brief NRG1 treatment (0.5–1.5 h) mobilizes KCa channels in a post-Golgi compartment, but longer treatments (>3.5 h) mobilize KCa channels located in the endoplasmic reticulum or Golgi apparatus. Specifically, the effects of 3.5 h NRG1 treatment were completely blocked by treatments that disrupt Golgi apparatus function. These include inhibition of microtubules, or inhibition of the ADP-ribosylation factor-1 (ARF1) system by brefeldin A, by over-expression of dominant-negative ARF1, or over-expression of an ARF1 GTPase-activating protein that blocks ARF1 cycling between GTP- and GDP-bound states. These treatments had no effect on stimulation of KCa evoked by 1.5 h treatment with NRG1, indicating that short-term responses to NRG1 do not require an intact Golgi apparatus. By contrast, both the acute and sustained effects of NRG1 were inhibited by treatments that block trafficking processes that occur close to the plasma membrane. Thus mobilization of KCa was blocked by treatments than inhibit ADP-ribosylation factor-6 (ARF6) signaling, including overexpression of dominant-negative ARF6, dominant-negative ARNO, or dominant-negative phospholipase D1. TGFβ1, the effects of which on KCa are much slower in onset, is unable to selectively mobilize channels in the post-Golgi pool, and its effects on KCa are completely blocked by inhibition of microtubules, Golgi function and also by plasma membrane ARF6 and phospholipase D1 signaling.

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