Interorganelle Trafficking of Ceramide Is Regulated by Phosphorylation-dependent Cooperativity between the PH and START Domains of CERT

Kumagai, Keigo; Kawano, Miyuki; Shinkai-Ouchi, Fumiko; Nishijima, Masahiro; Hanada, Kentaro

doi:10.1074/jbc.m702291200

Cited by 111 publications

(243 citation statements)

References 31 publications

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Section: Regulation Of Sphingolipid Transport and Turnovermentioning

confidence: 99%

“…In the case of CERT, the Hanada group has shown that phosphorylation inhibits CERT-dependent ceramide transport and that this phosphorylation is regulated by sphingolipid levels (Kumagai et al 2007). Specifically, pharmacologic inhibition of SPT or enzymatic degradation of plasma membrane sphingomyelin induces CERT dephosphorylation and activation, which may enable a compensatory increase in sphingolipid production (Kumagai et al 2007). An additional mechanism regulating sphingolipid transport is suggested from the fact that both CERT and FAPP2 contain pleckstrin homology (PH) domains that bind to phosphatidylinositol-4-phosphate (PI4P), a lipid that serves as a key Golgi marker (Di Paolo and De Camilli 2006).…”

Section: Regulation Of Sphingolipid Transport and Turnovermentioning

confidence: 99%

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Sphingolipid Homeostasis in the Endoplasmic Reticulum and Beyond

Breslow

2013

Cold Spring Harbor Perspectives in Biology

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Sphingolipids are a diverse group of lipids that have essential cellular roles as structural components of membranes and as potent signaling molecules. In recent years, a detailed picture has emerged of the basic biochemistry of sphingolipids-from their initial synthesis in the endoplasmic reticulum (ER), to their elaboration into complex glycosphingolipids, to their turnover and degradation. However, our understanding of how sphingolipid metabolism is regulated in response to metabolic demand and physiologic cues remains incomplete. Here I discuss new insights into the mechanisms that ensure sphingolipid homeostasis, with an emphasis on the ER as a critical regulatory site in sphingolipid metabolism. In particular, Orm family proteins have recently emerged as key ER-localized mediators of sphingolipid homeostasis. A detailed understanding of how cells sense and control sphingolipid production promises to provide key insights into membrane function in health and disease.

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Section: Regulation Of Sphingolipid Transport and Turnovermentioning

confidence: 99%

Section: Regulation Of Sphingolipid Transport and Turnovermentioning

confidence: 99%

Sphingolipid Homeostasis in the Endoplasmic Reticulum and Beyond

Breslow

2013

Cold Spring Harbor Perspectives in Biology

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“…This interaction is required for CERT to extract ceramide from the ER before transportation of ceramide to the Golgi apparatus. We also showed that the SR motif in CERT is phosphorylated at multiple Ser/Thr residues and that hyperphosphorylation of these sites results in down-regulation of ceramide trafficking function of CERT (21). We, therefore, were interested in determining whether PP2C⑀ associated with VAPA regulates CERT function through dephosphorylation.…”

Section: Pp2c⑀ Ismentioning

confidence: 99%

“…CERT consists of several distinct domains including a Steroidogenic acute regulator-related lipid transfer (START) domain capable of specifically extracting ceramide from membrane, a pleckstrin homology (PH) domain that serves to target the Golgi apparatus by recognizing phosphatidylinositol 4-monphophatate, and a FFAT motif, which interacts with VAPA. In addition to these functional domains, CERT possesses a regulatory sequence referred to as a serine repeat (SR) motif between the PH domain and FFAT motif (21). The Ser/ Thr residues of the SR motif are phosphorylated in vivo.…”

mentioning

confidence: 99%

“…These phosphorylation sites match the typical consensus motif for protein kinase CK1 in which Ser-132 would serve as priming phosphorylation site for sequential phosphorylation of downstream Ser/Thr residues within the motif. Enhanced phosphorylation of these sites results in down-regulation of CERT activity; under such conditions ceramide transport from the ER to the Golgi apparatus diminishes as a result of repression of both the ceramide transfer activity of the START domain and the phosphatidylinositol 4-monophosphate binding activity of the PH domain (21). A loss of SM and cholesterol from the plasma membrane induces dephosphorylation of the SR motif, resulting in activation of CERT.…”

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confidence: 99%

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Protein Phosphatase 2Cϵ Is an Endoplasmic Reticulum Integral Membrane Protein That Dephosphorylates the Ceramide Transport Protein CERT to Enhance Its Association with Organelle Membranes

Saito

Matsui

Kawano

et al. 2008

Journal of Biological Chemistry

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Protein phosphatase 2C⑀ (PP2C⑀), a mammalian PP2C family member, is expressed in various tissues and is implicated in the negative regulation of stress-activated protein kinase pathways. We show that PP2C⑀ is an endoplasmic reticulum (ER) transmembrane protein with a transmembrane domain at the amino terminus and the catalytic domain facing the cytoplasm. Yeast two-hybrid screening of a human brain library using PP2C⑀ as bait resulted in the isolation of a cDNA that encoded vesicle-associated membrane protein-associated protein A (VAPA). VAPA is an ER resident integral membrane protein involved in recruiting lipidbinding proteins such as the ceramide transport protein CERT to the ER membrane. Expression of PP2C⑀ resulted in dephosphorylation of CERT in a VAPA expression-dependent manner, which was accompanied by redistribution of CERT from the cytoplasm to the Golgi apparatus. The expression of PP2C⑀ also enhanced the association between CERT and VAPA. In addition, knockdown of PP2C⑀ expression by short interference RNA attenuated the interaction between CERT and VAPA and the sphingomyelin synthesis. These results suggest that CERT is a physiological substrate of PP2C⑀ and that dephosphorylation of CERT by PP2C⑀ may play an important role in the regulation of ceramide trafficking from the ER to the Golgi apparatus.Vesicle-associated membrane protein-associated protein A (VAPA) 3 is an endoplasmic reticulum (ER)-resident type II transmembrane protein with homologs widely distributed from yeast to human (1-3). Recently, evidence has accumulated that in mammalian cells VAPA participates in the regulation of inter-organelle transport of membrane lipids by recruiting lipid transfer proteins to the ER membrane. VAPA associates with a short, conserved peptide sequence termed the "two phenylalanines in an acidic tract" (FFAT) motif that is found in several lipid transfer proteins including ceramide transport protein CERT, oxysterol-binding protein, Opi1 protein, and PITP/Nir/ rdgB families (4 -11). VAPA is composed of two conserved domains, an amino-terminal immunoglobulin-like ␤ sheet responsible for FFAT motif binding and a carboxyl-terminal transmembrane domain (8). In addition to its role in recruiting FFAT motif-targeted proteins to ER membranes, VAPA has been proposed to function in vesicle trafficking (1,(12)(13)(14), in the organization of the microtubule network (10, 15), and in the replication of hepatitis C virus RNA (16,17). In mammalian cells ceramide is synthesized in the ER and transported to the Golgi apparatus where it is converted to sphingomyelin (SM). The ceramide transport protein CERT plays a key role in the ER-to-Golgi trafficking of ceramide (18 -20). CERT consists of several distinct domains including a Steroidogenic acute regulator-related lipid transfer (START) domain capable of specifically extracting ceramide from membrane, a pleckstrin homology (PH) domain that serves to target the Golgi apparatus by recognizing phosphatidylinositol 4-monphophatate, and a FFAT motif, which interacts with VA...

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Structure, functions and regulation of CERT, a lipid‐transfer protein for the delivery of ceramide at the ER–Golgi membrane contact sites

Kumagai

Hanada

2019

FEBS Letters

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The inter‐organelle transport of lipids must be regulated to ensure appropriate lipid composition of each organelle. In mammalian cells, ceramide synthesised in the endoplasmic reticulum (ER) is transported to the trans‐Golgi regions, where ceramide is converted to sphingomyelin (SM) with the concomitant production of diacylglycerol. Ceramide transport protein (CERT) transports ceramide from the ER to the trans‐Golgi regions at the ER–Golgi membrane contact sites (MCS). The function of CERT is down‐regulated by multisite phosphorylation of a serine‐repeat motif (SRM) and up‐regulated by phosphorylation of serine 315 in CERT. Multisite phosphorylation of the SRM is primed by protein kinase D, which is activated by diacylglycerol. The function of CERT is regulated by a phosphorylation‐dependent feedback mechanism in response to cellular requirements of SM. CERT‐dependent ceramide transport is also affected by the pool of phosphatidylinositol (PtdIns)‐4‐phosphate (PtdIns(4)P) in the trans‐Golgi regions, while the PtdIns(4)P pool is regulated by PtdIns‐4‐kinases and oxysterol‐binding protein. The ER‐Golgi MCS may serve as inter‐organelle communication zones, in which many factors work in concert to serve as an extensive rheostat of SM, diacylglycerol, cholesterol and PtdIns(4)P.

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Interorganelle Trafficking of Ceramide Is Regulated by Phosphorylation-dependent Cooperativity between the PH and START Domains of CERT

Cited by 111 publications

References 31 publications

Sphingolipid Homeostasis in the Endoplasmic Reticulum and Beyond

Sphingolipid Homeostasis in the Endoplasmic Reticulum and Beyond

Protein Phosphatase 2Cϵ Is an Endoplasmic Reticulum Integral Membrane Protein That Dephosphorylates the Ceramide Transport Protein CERT to Enhance Its Association with Organelle Membranes

Structure, functions and regulation of CERT, a lipid‐transfer protein for the delivery of ceramide at the ER–Golgi membrane contact sites

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