Binding between the Niemann–Pick C1 protein and a photoactivatable cholesterol analog requires a functional sterol-sensing domain

Ohgami, Nobutaka; Ko, Dennis C.; Thomas, Matthew A. M.; Scott, Matthew P.; Chang, Catherine C.Y.; Chang, Ta−Yuan

doi:10.1073/pnas.0405255101

Cited by 179 publications

(157 citation statements)

References 50 publications

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“…NPC2 is a soluble glycoprotein in the lumen of the late endosomes/ lysosomes (LE/LYS) (9). Both NPC1 and NPC2 bind to cholesterol (10)(11)(12)(13)(14)(15) and may cooperate in endosomal cholesterol transport (16). Whether the Golgi is involved in LDL-CHOL transport downstream of the NPC1 compartment has not yet been demonstrated.…”

Section: Transport Of Ldl-derived Cholesterol From the Npc1 Compartmementioning

confidence: 99%

Transport of LDL-derived cholesterol from the NPC1 compartment to the ER involves the trans-Golgi network and the SNARE protein complex

Urano

Watanabe

Murphy

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

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106

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Mammalian cells acquire cholesterol mainly from LDL. LDL enter the endosomes, allowing cholesteryl esters to be hydrolyzed by acid lipase. The hydrolyzed cholesterol (LDL-CHOL) enters the Niemann–Pick type C1 (NPC1)-containing endosomal compartment en route to various destinations. Whether the Golgi is involved in LDL-CHOL transport downstream of the NPC1 compartment has not been demonstrated. Using subcellular fractionation and immunoadsorption to enrich for specific membrane fractions, here we show that, when parental Chinese hamster ovary (CHO) cells are briefly exposed to 3 H-cholesteryl linoleate (CL) labeled-LDL, newly liberated 3 H-LDL-CHOL appears in membranes rich in trans-Golgi network (TGN) long before it becomes available for re-esterification at the endoplasmic reticulum (ER) or for efflux at the plasma membrane. In mutant cells lacking NPC1, the appearance of newly liberated 3 H-LDL-CHOL in the TGN-rich fractions is much reduced. We next report a reconstituted transport system that recapitulates the transport of LDL-CHOL to the TGN and to the ER. The transport system requires ATP and cytosolic factors and depends on functionality of NPC1. We demonstrate that knockdown by RNAi of 3 TGN-specific SNAREs (VAMP4, syntaxin 6, and syntaxin 16) reduces ≥50% of the LDL-CHOL transport in intact cells and in vitro. These results show that vesicular trafficking is involved in transporting a significant portion of LDL-CHOL from the NPC1-containing endosomal compartment to the TGN before its arrival at the ER.

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Section: Transport Of Ldl-derived Cholesterol From the Npc1 Compartmementioning

confidence: 99%

Transport of LDL-derived cholesterol from the NPC1 compartment to the ER involves the trans-Golgi network and the SNARE protein complex

Urano

Watanabe

Murphy

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

106

131

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“…Thus, it is still not known which of scenarios described above is of highest signifi cance during disease progression. Similarly, it has not been conclusively determined which of the lipids sequestered in NPC lysosomes is the primary culprit reaccumulate under NPC1 or NPC2 loss-of-function ( 21,67,68 ).…”

Section: Discussionmentioning

confidence: 99%

Altered vitamin E status in Niemann-Pick type C disease

Ulatowski

Parker

Davidson

et al. 2011

Journal of Lipid Research

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“…(9,10) PTCH1 is composed of N-and C-terminal domains, two large extracellular and one large intracellular loops, and 12-pass transmembrane domains, two to six of which form the putative sterol-sensing domain (SSD) considered to participate in vesicular trafficking of cholesterol and other lipids. (11,12) We and other groups have reported that more than 85% of patients with NBCCS harbor heterozygous germline PTCH1 mutations, (13)(14)(15) primarily consisting of PTCH1 protein truncations (73%) that are usually concentrated in the large extracellular and intracellular loops and in the N-terminal region. Germline missense mutations (17%) occur primarily in the transmembrane domains and especially in the SSDs.…”

Section: Introductionmentioning

confidence: 99%

Heterozygous PTCH1 Mutations Impact the Bone Metabolism in Patients With Nevoid Basal Cell Carcinoma Syndrome Likely by Regulating SPARC Expression

Hong

Zhang

et al. 2016

Journal of Bone and Mineral Research

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Nevoid basal cell carcinoma syndrome (NBCCS) is an autosomal dominant disorder characterized by bone and skin abnormalities and a predisposition to various tumors. Keratocystic odontogenic tumors (KCOTs), which are common tumors of the jaw that cause extensive damage to the jawbone, are usually accompanied with NBCCS. Germline PTCH1 mutations in NBCCS tumorigenesis have been frequently studied; however, little is known regarding the pathogenesis of bone abnormalities in this disease. This study sought to investigate the mechanism underlying heterozygous PTCH1 mutation-mediated abnormal bone metabolism in patients with NBCCS. Stromal cells were isolated from the fibrous capsules of patients with NBCCS-associated or non-syndromic keratocystic odontogenic tumors and non-syndromic tumor stromal cells without PTCH1 mutations served as controls. Germline PTCH1 heterozygous mutations were confirmed in all NBCCS samples and differential protein expression was identified using tandem mass tag-labeled proteomics analysis. Our findings revealed that osteonectin/SPARC expression was significantly downregulated in syndromic stromal cells compared with non-syndromic stromal cells. SPARC expression was even lower in stromal cells carrying PTCH1 protein truncation mutations. PTCH1 siRNA transfection demonstrated that SPARC downregulation correlates with decreased PTCH1 expression. Furthermore, exogenous SPARC promoted osteogenic differentiation of syndromic stromal cells with enhanced development of calcium nodules. In addition, bone mineral density tests showed that patients with NBCCS exhibit weak bone mass compared with sex-and age-matched controls. This study indicates that germline PTCH1 heterozygous mutations play a major role in bone metabolism in patients with NBCCS, in particular in those with PTCH1 protein truncation mutations. SPARC may represent an important downstream modulator of PTCH1 mediation of bone metabolism. Thus, bone mineral density monitoring is critical for patients with NBCCS for prevention of osteoporosis. In addition, surgical procedures on syndromic-associated KCOTs should be performed with consideration of the weaker bone mass in such patients.

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Binding between the Niemann–Pick C1 protein and a photoactivatable cholesterol analog requires a functional sterol-sensing domain

Cited by 179 publications

References 50 publications

Transport of LDL-derived cholesterol from the NPC1 compartment to the ER involves the trans-Golgi network and the SNARE protein complex

Transport of LDL-derived cholesterol from the NPC1 compartment to the ER involves the trans-Golgi network and the SNARE protein complex

Altered vitamin E status in Niemann-Pick type C disease

Heterozygous PTCH1 Mutations Impact the Bone Metabolism in Patients With Nevoid Basal Cell Carcinoma Syndrome Likely by Regulating SPARC Expression

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