Diacylglycerol kinase epsilon in bovine and rat photoreceptor cells. Light-dependent distribution in photoreceptor cells

Natalini, Paola M.; Zulian, Sandra E.; Boschero, Mónica G. Ilincheta de; Giusto, Norma M.

doi:10.1016/j.exer.2013.04.012

Cited by 5 publications

(7 citation statements)

References 42 publications

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“…DAGK 3 was demonstrated to be concentrated in the inner segment of the photoreceptor layer under dark condition. In contrast, under light stimuli, DAGK 3 was observed to be higher in the outer segment than the inner segment (Natalini et al, 2013). Representative images from immunohistochemistry assays showed that DAGK 3 appears to be also concentrated in nuclei of the photoreceptor layer (ONL) under dark conditions.…”

Section: Discussionmentioning

confidence: 90%

“…Our previous immunohistochemistry studies revealed a lightdependent localization of DAGK isoforms in different layers of rat retinas (Natalini et al, 2013). Interestingly, the outer nuclear layer, comprising small nucleus from photoreceptor cells, is one of these immunostained layers.…”

Section: Introductionmentioning

confidence: 87%

“…A 64 kDa isozyme with very high homology to human DAGK 3 has been shown to be present in rat retina (Kohyama-Koganeya et al, 1997). Although until 2012 DAGKg was the only isoform detected in light activated rods (Huang et al, 2000) we recently reported a light-dependent different distribution of DAGK 3 in bovine and rat photoreceptor cells (Natalini et al, 2013).…”

Section: Introductionmentioning

confidence: 93%

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A novel light-dependent activation of DAGK and PKC in bovine photoreceptor nuclei

Natalini

Mateos

Boschero

et al. 2014

Experimental Eye Research

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Section: Discussionmentioning

confidence: 90%

Section: Introductionmentioning

confidence: 87%

Section: Introductionmentioning

confidence: 93%

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A novel light-dependent activation of DAGK and PKC in bovine photoreceptor nuclei

Natalini

Mateos

Boschero

et al. 2014

Experimental Eye Research

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“…Both the lipid substrate (DAG) and product (PA) of the DGK⑀-catalyzed reaction have low water solubility. Until now, DGK⑀ activity assays have always been performed using mixed micelles (11,(15)(16)(17). However, these structures do not represent biological membranes, and it is difficult to systematically vary their physical properties.…”

Section: Marked Differences In Dgk⑀ Activity and Acyl-chain Specificimentioning

confidence: 99%

Membrane curvature allosterically regulates the phosphatidylinositol cycle, controlling its rate and acyl-chain composition of its lipid intermediates

Bozelli

Jennings

Black

et al. 2018

Journal of Biological Chemistry

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Edited by Paul E. FraserSignaling events at membranes are often mediated by membrane lipid composition or membrane physical properties. These membrane properties could act either by favoring the membrane binding of downstream effectors or by modulating their activity. Several proteins can sense/generate membrane physical curvature (i.e. shape). However, the modulation of the activity of enzymes by a membrane's shape has not yet been reported. Here, using a cell-free assay with purified diacylglycerol kinase ⑀ (DGK⑀) and liposomes, we studied the activity and acyl-chain specificity of an enzyme of the phosphatidylinositol (PI) cycle, DGK⑀. By systematically varying the model membrane lipid composition and physical properties, we found that DGK⑀ has low activity and lacks acyl-chain specificity in locally flat membranes, regardless of the lipid composition. On the other hand, these enzyme properties were greatly enhanced in membrane structures with a negative Gaussian curvature. We also found that this is not a consequence of preferential binding of the enzyme to those structures, but rather is due to a curvature-mediated allosteric regulation of DGK⑀ activity and acylchain specificity. Moreover, in a fine-tuned interplay between the enzyme and the membrane, DGK⑀ favored the formation of structures with greater Gaussian curvature. DGK⑀ does not bear a regulatory domain, and these findings reveal the importance of membrane curvature in regulating DGK⑀ activity and acyl-chain specificity. Hence, this study highlights that a hierarchic coupling of membrane physical property and lipid composition synergistically regulates membrane signaling events. We propose that this regulatory mechanism of membrane-associated enzyme activity is likely more common than is currently appreciated.

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“…In vitro assays used to test its activity all rely on simultaneous co-solubilization with detergent of DGKε from cells together with DAG (Epand and Topham, 2007 ). A recent report suggests that the detergent used in these assays can exert a strong influence on the degree of substrate specificity (Natalini et al, 2013 ). The use of membrane bilayers in the form of liposomes would avoid possible artifacts caused by the presence of detergent and would more closely simulate a biological membrane.…”

Section: Interaction With Diacylglycerolmentioning

confidence: 99%

Diacylglycerol Kinase-ε: Properties and Biological Roles

Epand

Jennings

et al. 2016

Front. Cell Dev. Biol.

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In mammals there are at least 10 isoforms of diacylglycerol kinases (DGK). All catalyze the phosphorylation of diacylglycerol (DAG) to phosphatidic acid (PA). Among DGK isoforms, DGKε has several unique features. It is the only DGK isoform with specificity for a particular species of DAG, i.e., 1-stearoyl-2-arachidonoyl glycerol. The smallest of all known DGK isoforms, DGKε, is also the only DGK devoid of a regulatory domain. DGKε is the only DGK isoform that has a hydrophobic segment that is predicted to form a transmembrane helix. As the only membrane-bound, constitutively active DGK isoform with exquisite specificity for particular molecular species of DAG, the functional overlap between DGKε and other DGKs is predicted to be minimal. DGKε exhibits specificity for DAG containing the same acyl chains as those found in the lipid intermediates of the phosphatidylinositol-cycle. It has also been shown that DGKε affects the acyl chain composition of phosphatidylinositol in whole cells. It is thus likely that DGKε is responsible for catalyzing one step in the phosphatidylinositol-cycle. Steps of this cycle take place in both the plasma membrane and the endoplasmic reticulum membrane. DGKε is likely present in both of these membranes. DGKε is the only DGK isoform that is associated with a human disease. Indeed, recessive loss-of-function mutations in DGKε cause atypical hemolytic-uremic syndrome (aHUS). This condition is characterized by thrombosis in the small vessels of the kidney. It causes acute renal insufficiency in infancy and most patients develop end-stage renal failure before adulthood. Disease pathophysiology is poorly understood and there is no therapy. There are also data suggesting that DGKε may play a role in epilepsy and Huntington disease. Thus, DGKε has many unique molecular and biochemical properties when compared to all other DGK isoforms. DGKε homologs also contain a number of conserved sequence features that are distinctive characteristics of either the rodents or specific groups of primate homologs. How cells, tissues and organisms harness DGKε's catalytic prowess remains unclear. The discovery of DGKε's role in causing aHUS will hopefully boost efforts to unravel the mechanisms by which DGKε dysfunction causes disease.

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Diacylglycerol kinase epsilon in bovine and rat photoreceptor cells. Light-dependent distribution in photoreceptor cells

Cited by 5 publications

References 42 publications

A novel light-dependent activation of DAGK and PKC in bovine photoreceptor nuclei

A novel light-dependent activation of DAGK and PKC in bovine photoreceptor nuclei

Membrane curvature allosterically regulates the phosphatidylinositol cycle, controlling its rate and acyl-chain composition of its lipid intermediates

Diacylglycerol Kinase-ε: Properties and Biological Roles

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