Phosphatidylinositol-4-phosphate 5-Kinase Isoforms Exhibit Acyl Chain Selectivity for Both Substrate and Lipid Activator

Shulga, Yulia V.; Anderson, Richard A.; Topham, Matthew K.; Epand, Richard M.

doi:10.1074/jbc.m112.370155

Cited by 55 publications

(64 citation statements)

References 71 publications

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“…The 15 N, 13 C–double-labeled peptide was prepared for NMR characterization. Similar to human PIP5K isoforms ( 11 ), zPIP5Kα exhibits clear preference toward PI(4)P with unsaturated acyl chains (fig. S1B).…”

Section: Resultsmentioning

confidence: 92%

“…It has been reported that the activity of PIP5K can be markedly modulated by fatty acid composition of the lipid substrates and phosphatidic acid ( 11 ). Our study reveals that PIP5K activity is also sensitive to the size/curvature of the membrane mimics.…”

Section: Resultsmentioning

confidence: 99%

“…The activity of PIP5K can be significantly modulated by the membrane lipid composition, and the phosphatidic acid is a known activator of PIP5K ( 11 ). These facts strongly suggest the presence of a membrane-sensing mechanism for PIP5K.…”

Section: Introductionmentioning

confidence: 99%

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The activation loop of PIP5K functions as a membrane sensor essential for lipid substrate processing

Liu

Sui

et al. 2016

Sci. Adv.

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Section: Resultsmentioning

confidence: 92%

Section: Resultsmentioning

confidence: 99%

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The activation loop of PIP5K functions as a membrane sensor essential for lipid substrate processing

Liu

Sui

et al. 2016

Sci. Adv.

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“…PIP acyl chains are likely to affect regulation and function because acyl chains affect the substrate preference of type I phosphatidylinositol phosphate kinases (PIPKI) and OCRL, which synthesize and degrade PI(4,5)P 2 , respectively (Schmid et al. , 2004; Shulga et al. , 2012).…”

Section: Introductionmentioning

confidence: 99%

The acyltransferase LYCAT controls specific phosphoinositides and related membrane traffic

Bone

Dayam

Lee

et al. 2017

MBoC

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Phosphoinositides (PIPs) are key regulators of membrane traffic and signaling. The interconversion of PIPs by lipid kinases and phosphatases regulates their functionality. Phosphatidylinositol (PI) and PIPs have a unique enrichment of 1-stearoyl-2-arachidonyl acyl species; however, the regulation and function of this specific acyl profile remains poorly understood. We examined the role of the PI acyltransferase LYCAT in control of PIPs and PIPdependent membrane traffic. LYCAT silencing selectively perturbed the levels and localization of phosphatidylinositol-4,5-bisphosphate [PI(4,5)P 2 ] and phosphatidylinositol-3-phosphate and the membrane traffic dependent on these specific PIPs but was without effect on phosphatidylinositol-4-phosphate or biosynthetic membrane traffic. The acyl profile of PI(4,5)P 2 was selectively altered in LYCAT-deficient cells, whereas LYCAT localized with phosphatidylinositol synthase. We propose that LYCAT remodels the acyl chains of PI, which is then channeled into PI(4,5)P 2 . Our observations suggest that the PIP acyl chain profile may exert broad control of cell physiology. INTRODUCTIONPhosphoinositides (PIPs) control many facets of cell physiology, such as nutrient uptake, receptor signaling, and cell adhesion by control of specific stages of membrane traffic (Di Paolo and De Camilli, 2006;Krauss and Haucke, 2007). Through the action of lipid kinases and phosphatases, PIPs can be interconverted into seven different species defined by phosphorylation of the inositol head group (Balla, 2013). Each of the seven PIPs exhibits unique enrichment within membrane compartments and helps to recruit a variety of cognate effector proteins. Phosphatidylinositol-4,5-bisphosphate (PI(4,5)P 2 ) and phosphatidylinositol-3-phosphate (PI(3)P) illustrate these concepts well.PI(4,5)P 2 predominates within the plasma membrane (PM) and regulates clathrin-mediated endocytosis (referred to here as endocytosis) to control the internalization of cell surface proteins such as transferrin (Tfn) receptor (TfR;Jost et al., 1998;Varnai et al., 2006;Zoncu et al., 2007;Posor et al., 2013). PI(4,5)P 2 binds to and recruits AP2 and other proteins, which, together with cargo molecules and clathrin, initiate the formation and assembly of clathrin-coated pits (CCPs; Gaidarov and Keen, 1999;Itoh et al., 2001;Jackson et al., 2010). CCPs couple cargo selection to membrane invagination and eventually undergo scission from the PM by the GTPase dynamin2 to yield endocytic vesicles (Conner and Schmid, 2003;McMahon and Boucrot, 2011). CCPs harbor lipid phosphatases such as synaptojanins and OCRL that mediate PI(4,5)P 2 turnover to control the efficiency of vesicle formation (Antonescu et al., 2011) and, afterMonitoring Editor

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“…Also, the method described here simplifies the analysis of PtdInsP levels by eliminating the acyl chains, which greatly increases the molecular diversity of PtdInsPs. But by the same token, this is also a key disadvantage, since deacylation of lipids leads to a loss of structural information regarding the acyl chain, an underappreciated aspect of PtdInsP signaling 41,42 . If this is of great concern, then liquid chromatography coupled to mass spectrometry (LC-MS) should be employed 14,17 .…”

Section: Discussionmentioning

confidence: 99%

Radiolabeling and Quantification of Cellular Levels of Phosphoinositides by High Performance Liquid Chromatography-coupled Flow Scintillation

Choy

Botelho

2016

JoVE

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Phosphoinositides (PtdInsPs) are essential signaling lipids responsible for recruiting specific effectors and conferring organelles with molecular identity and function. Each of the seven PtdInsPs varies in their distribution and abundance, which are tightly regulated by specific kinases and phosphatases. The abundance of PtdInsPs can change abruptly in response to various signaling events or disturbance of the regulatory machinery. To understand how these events lead to changes in the amount of PtdInsPs and their resulting impact, it is important to quantify PtdInsP levels before and after a signaling event or between control and abnormal conditions. However, due to their low abundance and similarity, quantifying the relative amounts of each PtdInsP can be challenging. This article describes a method for quantifying PtdInsP levels by metabolically labeling cells with 3 H-myo-inositol, which is incorporated into PtdInsPs. Phospholipids are then precipitated and deacylated. The resulting soluble 3 H-glycero-inositides are further extracted, separated by high-performance liquid chromatography (HPLC), and detected by flow scintillation. The labeling and processing of yeast samples is described in detail, as well as the instrumental setup for the HPLC and flow scintillator. Despite losing structural information regarding acyl chain content, this method is sensitive and can be optimized to concurrently quantify all seven PtdInsPs in cells. Video LinkThe video component of this article can be found at

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Phosphatidylinositol-4-phosphate 5-Kinase Isoforms Exhibit Acyl Chain Selectivity for Both Substrate and Lipid Activator

Cited by 55 publications

References 71 publications

The activation loop of PIP5K functions as a membrane sensor essential for lipid substrate processing

The activation loop of PIP5K functions as a membrane sensor essential for lipid substrate processing

The acyltransferase LYCAT controls specific phosphoinositides and related membrane traffic

Radiolabeling and Quantification of Cellular Levels of Phosphoinositides by High Performance Liquid Chromatography-coupled Flow Scintillation

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