cDNA and Genomic Cloning of Human Palmitoyl-Protein Thioesterase (PPT), the Enzyme Defective in Infantile Neuronal Ceroid Lipofuscinosis

Schriner, Julie E.; Yi, Won; Hofmann, Sandra L.

doi:10.1006/geno.1996.0292

Cited by 39 publications

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“…Invariant residues are shaded in black. The human, bovine, and rat PPT cDNA sequences have been published previously (3,26). The mouse PPT amino acid sequences were derived from the expressed sequence-tagged database using the BLAST algorithm of the NCBI, and are incomplete at the 5Ј and 3Ј ends.…”

Section: Discussionmentioning

confidence: 99%

Molecular genetics of palmitoyl-protein thioesterase deficiency in the U.S.

Das¹,

Becerra²,

Yi³

et al. 1998

J. Clin. Invest.

145

117

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Mutations in a newly described lysosomal enzyme, palmitoyl-protein thioesterase (PPT), were recently shown to be responsible for an autosomal recessive neurological disorder prevalent in Finland, infantile neuronal ceroid lipofuscinosis. The disease results in blindness, motor and cognitive deterioration, and seizures. Characteristic inclusion bodies (granular osmiophilic deposits [GROD]) are found in the brain and other tissues. The vast majority of Finnish cases are homozygous for a missense mutation (R122W) that severely affects PPT enzyme activity, and the clinical course in Finnish children is uniformly rapidly progressive and fatal.To define the clinical, biochemical, and molecular genetic characteristics of subjects with PPT deficiency in a broader population, we collected blood samples from U.S. and Canadian subjects representing 32 unrelated families with neuronal ceroid lipofuscinosis who had GROD documented morphologically. We measured PPT activity and screened the coding region of the PPT gene for mutations. In 29 of the families, PPT deficiency was found to be responsible for the neurodegenerative disorder, and mutations were identified in 57 out of 58 PPT alleles. One nonsense mutation (R151X) accounted for 40% of the alleles and was associated with severe disease in the homozygous state. A second mutation (T75P) accounted for 13% of the alleles and was associated with a late onset and protracted clinical course. A total of 19 different mutations were found, resulting in a broader spectrum of clinical presentations than previously seen in the Finnish population. Symptoms first appeared at ages ranging from 3 mo to 9 yr, and about half of the subjects have survived into the second or even third

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Section: Discussionmentioning

confidence: 99%

Molecular genetics of palmitoyl-protein thioesterase deficiency in the U.S.

Das¹,

Becerra²,

Yi³

et al. 1998

J. Clin. Invest.

145

117

View full text Add to dashboard Cite

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“…The enzyme was originally isolated by virtue of its ability to remove palmitate from the proto-oncoprotein H-Ras (7,8), but it has a broad substrate specificity, cleaving fatty acyl chains of lengths [14][15][16][17][18] carbons from cysteine residues in proteins and peptides as well as from palmitoyl-CoA (8) and S-palmitoyl thioglucoside (9). Palmitoylation is an important protein modification that facilitates membrane localization and protein-protein interactions (10).…”

Section: Nfantile Neuronal Ceroid Lipofuscinosis (Incl) Is the Mostmentioning

confidence: 99%

“…Bovine PPT1 is 95% identical to human PPT1 at the amino acid level (14). The structure has been refined to 2.25 Å resolution.…”

Section: Nfantile Neuronal Ceroid Lipofuscinosis (Incl) Is the Mostmentioning

confidence: 99%

The crystal structure of palmitoyl protein thioesterase 1 and the molecular basis of infantile neuronal ceroid lipofuscinosis

Bellizzi

Widom

Kemp

et al. 2000

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

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143

125

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Mutations in palmitoyl-protein thioesterase 1 (PPT1), a lysosomal enzyme that removes fatty acyl groups from cysteine residues in modified proteins, cause the fatal inherited neurodegenerative disorder infantile neuronal ceroid lipofuscinosis. The accumulation of undigested substrates leads to the formation of neuronal storage bodies that are associated with the clinical symptoms. Less severe forms of PPT1 deficiency have been found recently that are caused by a distinct set of PPT1 mutations, some of which retain a small amount of thioesterase activity. We have determined the crystal structure of PPT1 with and without bound palmitate by using multiwavelength anomalous diffraction phasing. The structure reveals an ␣͞␤-hydrolase fold with a catalytic triad composed of Ser115-His289-Asp233 and provides insights into the structural basis for the phenotypes associated with PPT1 mutations.

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“…cDNA Cloning of Human PPT2-A contiguous alignment of homologous sequences was established using the published sequence of human PPT1 (14) and a number of expressed sequence-tagged human clones using the BLAST algorithm of the NCBI. Two clones (N24410 and H86385, designated A and B, respectively, in Fig.…”

Section: Materials-the Genetrappermentioning

confidence: 99%

Molecular Cloning and Expression of Palmitoyl-protein Thioesterase 2 (PPT2), a Homolog of Lysosomal Palmitoyl-protein Thioesterase with a Distinct Substrate Specificity

Soyombo

Hofmann

1997

Journal of Biological Chemistry

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100

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Palmitoyl-protein thioesterase is a lysosomal hydrolase that removes long chain fatty acyl groups from modified cysteine residues in proteins. Mutations in this enzyme were recently shown to underlie the hereditary neurodegenerative disorder, infantile neuronal ceroid lipofuscinosis, and lipid thioesters derived from acylated proteins were found to accumulate in lymphoblasts from individuals with the disorder. In the current study, we describe the cloning and expression of a second lysosomal thioesterase, palmitoyl-protein thioesterase 2 (PPT2), that shares an 18% identity with palmitoylprotein thioesterase. Transient expression of a PPT2 cDNA led to the production of a glycosylated lysosomal protein with palmitoyl-CoA hydrolase activity comparable with palmitoyl-protein thioesterase. However, PPT2 did not remove palmitate groups from palmitoylated proteins that are substrates for palmitoyl-protein thioesterase. In cross-correction experiments, PPT2 did not abolish the accumulation of protein-derived lipid thioesters in palmitoyl-protein thioesterase-deficient cell lines. These results indicate that PPT2 is a lysosomal thioesterase that possesses a substrate specificity that is distinct from that of palmitoyl-protein thioesterase.A growing number of proteins have been shown to undergo post-translational modification by fatty acids that are covalently linked to cysteine residues through a thioester bond (reviewed in Ref. 1). Usually, the modified cysteine residue is located in close proximity to the inner surface of the plasma membrane, and palmitate is the most commonly occurring fatty acid, although stearate, oleate, arachidonate, and small amounts of other fatty acids have also been described. Fatty acid modifications may contribute to intracellular protein localization by facilitating membrane binding and also by strengthening protein-protein interactions (reviewed in Ref. 2). It is also possible that the palmitate plays a structural role that is unique to each modified protein. Cycles of palmitoylation and depalmitoylation have been described for a number of intracellular proteins (3), but the relevant enzyme(s) that catalyze these processes have not been isolated or fully characterized, and the full significance of these cycles remains to be elucidated.In an initial attempt to study the mechanism of depalmitoylation of Ha-Ras, we purified and cloned a thioesterase (palmitoyl-protein thioesterase, which will be referred to as PPT1) 1 that preferentially removes fatty acyl chains of 14 -18 carbons (i.e. myristate, palmitate, stearate, and oleate) from proteins in vitro (4, 5). Although PPT1 was originally purified from the soluble fraction of bovine brain, it was later found to be targeted to lysosomes (6 -8). Mutations in PPT1 were recently found to cause the infantile form of neuronal ceroid lipofuscinosis (INCL) (9), a neurovisceral storage disorder. This disease is characterized by the accumulation of amorphous granular deposits in cortical neurons leading to early visual loss and progressive mental deter...

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cDNA and Genomic Cloning of Human Palmitoyl-Protein Thioesterase (PPT), the Enzyme Defective in Infantile Neuronal Ceroid Lipofuscinosis

Cited by 39 publications

References 0 publications

Molecular genetics of palmitoyl-protein thioesterase deficiency in the U.S.

Molecular genetics of palmitoyl-protein thioesterase deficiency in the U.S.

The crystal structure of palmitoyl protein thioesterase 1 and the molecular basis of infantile neuronal ceroid lipofuscinosis

Molecular Cloning and Expression of Palmitoyl-protein Thioesterase 2 (PPT2), a Homolog of Lysosomal Palmitoyl-protein Thioesterase with a Distinct Substrate Specificity

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