Proteome-wide Dysregulation by PRA1 Depletion Delineates a Role of PRA1 in Lipid Transport and Cell Migration

Liu, Hao‐Ping; Wu, Chih‐Ching; Kao, Hung-Yi; Huang, Yongshun; Li, Ying; Chen, Chia Chun; Yu, Jau‐Song; Chang, Yu‐Sun

doi:10.1074/mcp.m900641-mcp200

Cited by 17 publications

(27 citation statements)

References 84 publications

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“…Of PRA1, about two-thirds was depleted upon NDRG1 silencing. PRA1 has been shown to interact with NDRG1 and regulate several endosomal Rab GTPases, including Rabs 4, 5, 7 and 9 (Bucci et al, 1999;Sivars et al, 2003), and to affect the endosomal cholesterol content (Liu et al, 2011). Moreover, we found that PRA1 overexpression alleviates the LDLR redistribution in NDRG1-silenced cells.…”

Section: Ndrg1 As a Regulator Of Endosomal Morphology And Functionsupporting

confidence: 53%

NDRG1 functions in LDL receptor trafficking by regulating endosomal recycling and degradation

Pietiäinen

Vassilev

Blom

et al. 2013

Journal of Cell Science

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Summary N-myc downstream-regulated gene 1 (NDRG1) mutations cause Charcot-Marie-Tooth disease type 4D (CMT4D). However, the cellular function of NDRG1 and how it causes CMT4D are poorly understood. We report that NDRG1 silencing in epithelial cells results in decreased uptake of low-density lipoprotein (LDL) due to reduced LDL receptor (LDLR) abundance at the plasma membrane. This is accompanied by the accumulation of LDLR in enlarged EEA1-positive endosomes that contain numerous intraluminal vesicles and sequester ceramide. Concomitantly, LDLR ubiquitylation is increased but its degradation is reduced and ESCRT (endosomal sorting complex required for transport) proteins are downregulated. Co-depletion of IDOL (inducible degrader of the LDLR), which ubiquitylates the LDLR and promotes its degradation, rescues plasma membrane LDLR levels and LDL uptake. In murine oligodendrocytes, Ndrg1 silencing not only results in reduced LDL uptake but also in downregulation of the oligodendrocyte differentiation factor Olig2. Both phenotypes are rescued by co-silencing of Idol, suggesting that ligand uptake through LDLR family members controls oligodendrocyte differentiation. These findings identify NDRG1 as a novel regulator of multivesicular body formation and endosomal LDLR trafficking. The deficiency of functional NDRG1 in CMT4D might impair lipid processing and differentiation of myelinating cells.

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Section: Ndrg1 As a Regulator Of Endosomal Morphology And Functionsupporting

confidence: 53%

NDRG1 functions in LDL receptor trafficking by regulating endosomal recycling and degradation

Pietiäinen

Vassilev

Blom

et al. 2013

Journal of Cell Science

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“…Sivars and colleagues [43] proposed a third function of PRA1 as a guanine nucleotide dissociation inhibitor (GDI) displacement factor (GDF) that aids in recycling Rabs during vesicular trafficking. An additional role for PRA1 in lipid transport, modulation of lipid homeostasis, and cell migration has been proposed based on proteomic analysis of PRA1 depleted nasopharyngeal carcinoma cells [44] and further supported by studies implicating PRA1 in the fusion of transport vesicles with the plasma membrane [45]. Finally, evidence supports a role for PRA1 in transport and assembly of viral proteins, although in some cases it may play an inhibitory role [45-49].…”

Section: Discussionmentioning

confidence: 98%

“…The PRA1-LIR intensity in the perinuclear region of the rd1 GCL is also reduced at P21, consistent with a possible role of PRA1 in neurite remodeling and sprouting. Virtually all of the proteins altered in PRA1-depleted nasopharyngeal carcinoma cells that are linked to changes in cell migration [44] are also known to be important in neurite outgrowth. In the inner retina we found similar average intensities of PRA1-LIR at all time points examined except at P8, most likely an anomalous result due to small sample size.…”

Section: Discussionmentioning

confidence: 99%

A role for prenylated rab acceptor 1 in vertebrate photoreceptor development

et al. 2012

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BackgroundThe rd1 mouse retina is a well-studied model of retinal degeneration where rod photoreceptors undergo cell death beginning at postnatal day (P) 10 until P21. This period coincides with photoreceptor terminal differentiation in a normal retina. We have used the rd1 retina as a model to investigate early molecular defects in developing rod photoreceptors prior to the onset of degeneration.ResultsUsing a microarray approach, we performed gene profiling comparing rd1 and wild type (wt) retinas at four time points starting at P2, prior to any obvious biochemical or morphological differences, and concluding at P8, prior to the initiation of cell death. Of the 143 identified differentially expressed genes, we focused on Rab acceptor 1 (Rabac1), which codes for the protein Prenylated rab acceptor 1 (PRA1) and plays an important role in vesicular trafficking. Quantitative RT-PCR analysis confirmed reduced expression of PRA1 in rd1 retina at all time points examined. Immunohistochemical observation showed that PRA1-like immunoreactivity (LIR) co-localized with the cis-Golgi marker GM-130 in the photoreceptor as the Golgi translocated from the perikarya to the inner segment during photoreceptor differentiation in wt retinas. Diffuse PRA1-LIR, distinct from the Golgi marker, was seen in the distal inner segment of wt photoreceptors starting at P8. Both plexiform layers contained PRA1 positive punctae independent of GM-130 staining during postnatal development. In the inner retina, PRA1-LIR also colocalized with the Golgi marker in the perinuclear region of most cells. A similar pattern was seen in the rd1 mouse inner retina. However, punctate and significantly reduced PRA1-LIR was present throughout the developing rd1 inner segment, consistent with delayed photoreceptor development and abnormalities in Golgi sorting and vesicular trafficking.ConclusionsWe have identified genes that are differentially regulated in the rd1 retina at early time points, which may give insights into developmental defects that precede photoreceptor cell death. This is the first report of PRA1 expression in the retina. Our data support the hypothesis that PRA1 plays an important role in vesicular trafficking between the Golgi and cilia in differentiating and mature rod photoreceptors.

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“…We used a ProteinProphet probability score of Ն 0.90 to ensure an overall false positive rate below 1%, and excluded proteins identified with only a single peptide hit. Protein quantification was achieved with the Libra program (38,39,43), using the default setting. A weighted average of the peptide iTRAQ ratios per protein was used to quantify the protein.…”

Section: Methodsmentioning

confidence: 99%

Interactome-wide Analysis Identifies End-binding Protein 1 as a Crucial Component for the Speck-like Particle Formation of Activated Absence in Melanoma 2 (AIM2) Inflammasomes

Wang

Hsu

Chen

et al. 2012

Molecular & Cellular Proteomics

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Inflammasomes are cytoplasmic receptors that can recognize intracellular pathogens or danger signals and are critical for interleukin 1␤ production. Although several key components of inflammasome activation have been identified, there has not been a systematic analysis of the protein components found in the stimulated complex. In this study, we used the isobaric tags for relative and absolute quantification approach to systemically analyze the interactomes of the NLRP3, AIM2, and RIG-I inflammasomes in nasopharyngeal carcinoma cells treated with specific stimuli of these interactomes (H 2 O 2 , poly (dA:dT), and EBV noncoding RNA, respectively). We identified a number of proteins that appeared to be involved in the interactomes and also could be precipitated with antiapoptosis-associated speck-like protein containing caspase activation and recruitment domain antibodies after stimulation. Among them, end binding protein 1 was an interacting component in all three interactomes. Silencing of end binding protein 1 expression by small interfering RNA inhibited the activation of the three inflammasomes, as indicated by reduced levels of interleukin 1␤ secretion. We confirmed that end binding protein 1 directly interacted with AIM2 and ASC in vitro and in vivo. Most importantly, fluorescence confocal microscopy showed that end binding protein 1 was required for formation of the speck-like particles that represent activation of the AIM2 inflammasome. In nasopharyngeal carcinoma tissues, immunohistochemical staining showed that end binding protein 1 expression was elevated and significantly correlated with AIM2 and ASC expression in nasopharyngeal carcinoma tumor cells. In sum, we profiled the interactome components of three inflammasomes and show for the first time that end binding protein 1 is crucial for the speck-like particle formation that represents activated inflammasomes. Molecular & Cellular

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Proteome-wide Dysregulation by PRA1 Depletion Delineates a Role of PRA1 in Lipid Transport and Cell Migration

Cited by 17 publications

References 84 publications

NDRG1 functions in LDL receptor trafficking by regulating endosomal recycling and degradation

NDRG1 functions in LDL receptor trafficking by regulating endosomal recycling and degradation

A role for prenylated rab acceptor 1 in vertebrate photoreceptor development

Interactome-wide Analysis Identifies End-binding Protein 1 as a Crucial Component for the Speck-like Particle Formation of Activated Absence in Melanoma 2 (AIM2) Inflammasomes

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