Pnkd encodes a metallo-beta-lactamase-fold protein of the glyoxalase II (hydroxyacylglutathione hydrolase) family, the PNKD subfamily, expressed in neurons throughout the brain. Alternative splicing produces a long membrane-associated isoform carrying the full zinc-binding hydrolase domain, a medium isoform, and a short isoform that lacks the catalytic domain and is found in cytoplasm and mitochondria. The long isoform is a probable zinc-dependent thioesterase: the human ortholog hydrolyses S-D-lactoylglutathione only at a trace rate and is not a functional glyoxalase II in vivo, so its physiological substrate is thought to be an unidentified alpha-hydroxythioester, possibly in a glutathione-linked detoxification reaction; Pnkd-null mouse cortex has lower glutathione. The long isoform undergoes N-terminal cleavage that is blocked by dominant dyskinesia-causing mutations. In mouse brain Pnkd binds the active-zone scaffolds RIM1 and RIM2, localises to presynaptic terminals, stabilises RIM proteins, and modulates synaptic vesicle exocytosis; mutations equivalent to human paroxysmal nonkinesigenic dyskinesia (DYT8) alleles cause stress-, caffeine- and ethanol-precipitated dyskinesia and nigrostriatal dopamine release defects in mice.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0004416 hydroxyacylglutathione hydrolase activity | IEA GO_REF:0000002 | MARK AS OVER ANNOTATED | Summary: InterPro2GO mapping of the hydroxyacylglutathione hydrolase signature (IPR017782) to the PNKD subfamily. Reason: Pnkd sits in PANTHER subfamily PTHR11935:SF116 (PNKD-related), not in the HAGH/glyoxalase II subfamily. The ortholog human PNKD-L hydrolyses S-D-lactoylglutathione only at an extremely low rate that the authors judge not physiologically relevant, and it fails to rescue SLG hydrolysis in hagh-null Drosophila. PAINT propagated only the parent thiolester hydrolase activity to this clade and not hydroxyacylglutathione hydrolase activity, which I treat as a deliberate decision. The general thiolester hydrolase activity (GO:0016790) is the appropriate claim; glyoxalase II activity overstates the evidence. Not assayed on the mouse protein. Supporting Evidence: PMID:21487022 This indicates that hydrolysis of SLG in vivo by PNKD-L is unlikely to be physiologically relevant. PMID:21487022 further supporting the idea that PNKD-L does not use SLG as an in vivo substrate file:mouse/Pnkd/Pnkd-uniprot.txt PTHR11935:SF116; HYDROLASE PNKD-RELATED |
| GO:0005515 protein binding | IPI PMID:25730884 Protein mutated in paroxysmal dyskinesia interacts with the ... | REMOVE | Summary: IPI from co-immunoprecipitation of Pnkd with RIM1 (Rims1) or RIM2 (Rims2) from mouse cortex and in HEK293 cells. Reason: Bare protein binding is uninformative and is removed under the GO:0005515 policy; removal does not dispute the reported Pnkd-RIM1/RIM2 interaction, which is well supported (endogenous pull-down from mouse frontal cortex, absent in Pnkd-/-). No specific GO MF term for RIM binding exists, and the interaction is captured in the description and in the neurotransmitter-secretion process rows. Supporting Evidence: PMID:25730884 confirmed that both RIM1 and RIM2 were pulled down by Pnkd from wild-type |
| GO:0005515 protein binding | IPI PMID:25730884 Protein mutated in paroxysmal dyskinesia interacts with the ... | REMOVE | Summary: IPI from co-immunoprecipitation of Pnkd with RIM1 (Rims1) or RIM2 (Rims2) from mouse cortex and in HEK293 cells. Reason: Bare protein binding is uninformative and is removed under the GO:0005515 policy; removal does not dispute the reported Pnkd-RIM1/RIM2 interaction, which is well supported (endogenous pull-down from mouse frontal cortex, absent in Pnkd-/-). No specific GO MF term for RIM binding exists, and the interaction is captured in the description and in the neurotransmitter-secretion process rows. Supporting Evidence: PMID:25730884 confirmed that both RIM1 and RIM2 were pulled down by Pnkd from wild-type |
| GO:0005737 cytoplasm | IEA GO_REF:0000120 | KEEP AS NON CORE | Summary: Cytoplasm, from ARBA/SubCell mapping and transfer from human PNKD (short isoform cytoplasmic). Reason: PNKD is recovered in both membrane and cytosolic fractions, and UniProt places the short isoform (isoform 2, which lacks the metallo-beta-lactamase domain) in the cytoplasm. The term is correct but broad; the more precise mouse location supported experimentally is presynaptic cytosol (IDA) and mitochondrion. Kept as non-core because it describes the catalytically inactive short isoform and soluble pools rather than the membrane-associated long isoform. Supporting Evidence: PMID:21487022 The PNKD protein (upper panel PNKD-L and lower panel PNKD-S) is found in both membrane and cytosolic fractions. |
| GO:0005737 cytoplasm | ISO GO_REF:0000119 | KEEP AS NON CORE | Summary: Cytoplasm, from ARBA/SubCell mapping and transfer from human PNKD (short isoform cytoplasmic). Reason: PNKD is recovered in both membrane and cytosolic fractions, and UniProt places the short isoform (isoform 2, which lacks the metallo-beta-lactamase domain) in the cytoplasm. The term is correct but broad; the more precise mouse location supported experimentally is presynaptic cytosol (IDA) and mitochondrion. Kept as non-core because it describes the catalytically inactive short isoform and soluble pools rather than the membrane-associated long isoform. Supporting Evidence: PMID:21487022 The PNKD protein (upper panel PNKD-L and lower panel PNKD-S) is found in both membrane and cytosolic fractions. |
| GO:0005737 cytoplasm | ISS GO_REF:0000024 | KEEP AS NON CORE | Summary: Cytoplasm, from ARBA/SubCell mapping and transfer from human PNKD (short isoform cytoplasmic). Reason: PNKD is recovered in both membrane and cytosolic fractions, and UniProt places the short isoform (isoform 2, which lacks the metallo-beta-lactamase domain) in the cytoplasm. The term is correct but broad; the more precise mouse location supported experimentally is presynaptic cytosol (IDA) and mitochondrion. Kept as non-core because it describes the catalytically inactive short isoform and soluble pools rather than the membrane-associated long isoform. Supporting Evidence: PMID:21487022 The PNKD protein (upper panel PNKD-L and lower panel PNKD-S) is found in both membrane and cytosolic fractions. |
| GO:0005739 mitochondrion | HDA PMID:18614015 A mitochondrial protein compendium elucidates complex I dise... | ACCEPT | Summary: MitoCarta mass-spectrometry compendium of mouse mitochondrial proteins. Reason: Mitochondrial localization is supported in mouse by the MitoCarta proteomic compendium (peptides unique to the short isoform detected repeatedly across tissues) and in human by direct localization studies, and PAINT placed mitochondrion at the PTN000940186 node covering mouse and human PNKD. Localization is isoform-dependent and contested for the long isoform (Shen et al. 2011 found human PNKD-L at the cell membrane, not mitochondria), but mitochondrion is a well-supported location for the gene product. Supporting Evidence: PMID:21487022 there was strong support for the short isoform to be localized to mitochondria |
| GO:0005739 mitochondrion | IBA GO_REF:0000033 | ACCEPT | Summary: PAINT IBA from PTN000940186 (mitochondrion), with human PNKD as donor. Reason: Mitochondrial localization is supported in mouse by the MitoCarta proteomic compendium (peptides unique to the short isoform detected repeatedly across tissues) and in human by direct localization studies, and PAINT placed mitochondrion at the PTN000940186 node covering mouse and human PNKD. Localization is isoform-dependent and contested for the long isoform (Shen et al. 2011 found human PNKD-L at the cell membrane, not mitochondria), but mitochondrion is a well-supported location for the gene product. Supporting Evidence: PMID:21487022 there was strong support for the short isoform to be localized to mitochondria |
| GO:0005739 mitochondrion | IEA GO_REF:0000120 | ACCEPT | Summary: Combined automated annotation from human ortholog and UniProt SubCell. Reason: Mitochondrial localization is supported in mouse by the MitoCarta proteomic compendium (peptides unique to the short isoform detected repeatedly across tissues) and in human by direct localization studies, and PAINT placed mitochondrion at the PTN000940186 node covering mouse and human PNKD. Localization is isoform-dependent and contested for the long isoform (Shen et al. 2011 found human PNKD-L at the cell membrane, not mitochondria), but mitochondrion is a well-supported location for the gene product. Supporting Evidence: PMID:21487022 there was strong support for the short isoform to be localized to mitochondria |
| GO:0005739 mitochondrion | ISO GO_REF:0000119 | ACCEPT | Summary: Transfer from human PNKD experimental mitochondrial localization. Reason: Mitochondrial localization is supported in mouse by the MitoCarta proteomic compendium (peptides unique to the short isoform detected repeatedly across tissues) and in human by direct localization studies, and PAINT placed mitochondrion at the PTN000940186 node covering mouse and human PNKD. Localization is isoform-dependent and contested for the long isoform (Shen et al. 2011 found human PNKD-L at the cell membrane, not mitochondria), but mitochondrion is a well-supported location for the gene product. Supporting Evidence: PMID:21487022 there was strong support for the short isoform to be localized to mitochondria |
| GO:0005739 mitochondrion | ISS GO_REF:0000024 | ACCEPT | Summary: UniProt similarity transfer from human PNKD. Reason: Mitochondrial localization is supported in mouse by the MitoCarta proteomic compendium (peptides unique to the short isoform detected repeatedly across tissues) and in human by direct localization studies, and PAINT placed mitochondrion at the PTN000940186 node covering mouse and human PNKD. Localization is isoform-dependent and contested for the long isoform (Shen et al. 2011 found human PNKD-L at the cell membrane, not mitochondria), but mitochondrion is a well-supported location for the gene product. Supporting Evidence: PMID:21487022 there was strong support for the short isoform to be localized to mitochondria |
| GO:0005783 endoplasmic reticulum | ISO GO_REF:0000119 | KEEP AS NON CORE | Summary: Transfer from human PNKD: ER localization of the medium isoform in overexpression studies. Reason: Derives from overexpression of the human PNKD-M isoform in Cos7 cells, which localised to Golgi, ER and plasma membrane. Plausible as a biosynthetic/trafficking compartment for the membrane-associated isoform but not where its function has been shown; kept as non-core. Supporting Evidence: PMID:21487022 PNKD-M localized to the Golgi apparatus, ER and plasma membrane |
| GO:0005794 Golgi apparatus | ISO GO_REF:0000119 | KEEP AS NON CORE | Summary: Transfer from human PNKD: Golgi localization of the medium isoform in overexpression studies. Reason: As for ER: from overexpressed human PNKD-M in Cos7 cells. Plausible trafficking compartment; non-core. Supporting Evidence: PMID:21487022 PNKD-M localized to the Golgi apparatus, ER and plasma membrane |
| GO:0005886 plasma membrane | IEA GO_REF:0000044 | ACCEPT | Summary: UniProt SubCell mapping (cell membrane, isoform 1). Reason: The long isoform of human PNKD localises in a cell-membrane pattern in SH-SY5Y and Cos7 cells; in mouse brain one Pnkd isoform is membrane-associated and Pnkd is found in the synaptic membrane fraction of cortical synaptosomes. Human and mouse PNKD are one-to-one orthologs in the same PANTHER subfamily, so the transfer is sound. Plasma membrane (as a peripheral membrane protein) is a core location of the long, enzymatically relevant isoform. Supporting Evidence: PMID:21487022 PNKD-L antibody staining revealed that the long isoform of human PNKD localizes in a cell membrane pattern in both cell lines. PMID:22214848 One PNKD isoform is a membrane-associated protein. PMID:25730884 Pnkd was detected in the synaptic membrane fraction along with RIM and GluR2 proteins |
| GO:0005886 plasma membrane | ISO GO_REF:0000119 | ACCEPT | Summary: Transfer from human PNKD experimental plasma-membrane localization. Reason: The long isoform of human PNKD localises in a cell-membrane pattern in SH-SY5Y and Cos7 cells; in mouse brain one Pnkd isoform is membrane-associated and Pnkd is found in the synaptic membrane fraction of cortical synaptosomes. Human and mouse PNKD are one-to-one orthologs in the same PANTHER subfamily, so the transfer is sound. Plasma membrane (as a peripheral membrane protein) is a core location of the long, enzymatically relevant isoform. Supporting Evidence: PMID:21487022 PNKD-L antibody staining revealed that the long isoform of human PNKD localizes in a cell membrane pattern in both cell lines. PMID:22214848 One PNKD isoform is a membrane-associated protein. PMID:25730884 Pnkd was detected in the synaptic membrane fraction along with RIM and GluR2 proteins |
| GO:0005886 plasma membrane | ISS GO_REF:0000024 | ACCEPT | Summary: UniProt similarity transfer from human PNKD. Reason: The long isoform of human PNKD localises in a cell-membrane pattern in SH-SY5Y and Cos7 cells; in mouse brain one Pnkd isoform is membrane-associated and Pnkd is found in the synaptic membrane fraction of cortical synaptosomes. Human and mouse PNKD are one-to-one orthologs in the same PANTHER subfamily, so the transfer is sound. Plasma membrane (as a peripheral membrane protein) is a core location of the long, enzymatically relevant isoform. Supporting Evidence: PMID:21487022 PNKD-L antibody staining revealed that the long isoform of human PNKD localizes in a cell membrane pattern in both cell lines. PMID:22214848 One PNKD isoform is a membrane-associated protein. PMID:25730884 Pnkd was detected in the synaptic membrane fraction along with RIM and GluR2 proteins |
| GO:0016020 membrane | IEA GO_REF:0000107 | MODIFY | Summary: Ensembl Compara transfer of human membrane annotation. Reason: Correct but general. The supporting work shows a membrane-associated Pnkd isoform in mouse brain and a cell-membrane localization of the long isoform, so the specific supported term is plasma membrane (GO:0005886), which the gene already carries. Proposed replacements: plasma membrane Supporting Evidence: PMID:22214848 One PNKD isoform is a membrane-associated protein. PMID:21487022 PNKD-L antibody staining revealed that the long isoform of human PNKD localizes in a cell membrane pattern in both cell lines. |
| GO:0016020 membrane | ISO PMID:22214848 Dopamine dysregulation in a mouse model of paroxysmal nonkin... | MODIFY | Summary: Transfer from human PNKD membrane annotation based on PMID:22214848 (which in fact studied mouse Pnkd). Reason: Correct but general. The supporting work shows a membrane-associated Pnkd isoform in mouse brain and a cell-membrane localization of the long isoform, so the specific supported term is plasma membrane (GO:0005886), which the gene already carries. Proposed replacements: plasma membrane Supporting Evidence: PMID:22214848 One PNKD isoform is a membrane-associated protein. PMID:21487022 PNKD-L antibody staining revealed that the long isoform of human PNKD localizes in a cell membrane pattern in both cell lines. |
| GO:0016790 thiolester hydrolase activity | IBA GO_REF:0000033 | ACCEPT | Summary: PAINT IBA from node PTN004322580 (thiolester hydrolase activity) in the metallo-beta-lactamase/glyoxalase II family. Reason: Pnkd is in PTHR11935:SF116 within the PTN004322580 clade. Its metallo-beta-lactamase domain retains the full zinc-binding THxHxDH motif (H172, H174, D176, H177) and the other zinc ligands (H229, D253, H291), so the catalytic machinery appears intact. The human ortholog shows measurable (though very weak) thioester hydrolysis of S-D-lactoylglutathione, and the physiological substrate is proposed to be an unknown alpha-hydroxythioester. Thiolester hydrolase activity is the appropriate general level; this is the core molecular function, but it is inferred phylogenetically and from the human enzyme assay, not measured on the mouse protein. Supporting Evidence: file:mouse/Pnkd/Pnkd-uniprot.txt PTHR11935:SF116; HYDROLASE PNKD-RELATED file:mouse/Pnkd/Pnkd-uniprot.txt Belongs to the metallo-beta-lactamase superfamily. PMID:21487022 Sequence alignment and enzyme kinetics suggest that PNKD-L substrate may be an (as yet, unknown) Ξ±-hydroxythioester PMID:21487022 This indicates that hydrolysis of SLG in vivo by PNKD-L is unlikely to be physiologically relevant. |
| GO:0032225 regulation of synaptic transmission, dopaminergic | IMP PMID:22214848 Dopamine dysregulation in a mouse model of paroxysmal nonkin... | KEEP AS NON CORE | Summary: IMP: Pnkd mutant (knock-in of patient-equivalent mutations) mice show nigrostriatal dopaminergic transmission deficits. Reason: Mouse experimental; qualifier acts_upstream_of_or_within. The knock-in mice have reduced striatal extracellular dopamine and exaggerated release to caffeine/ethanol. This is consistent with the later demonstration that Pnkd is a presynaptic RIM-binding regulator of release, but the dopaminergic phenotype itself is a circuit-level read-out of a mutant allele rather than evidence for a direct molecular role. Kept, as non-core. Supporting Evidence: PMID:22214848 They also showed nigrostriatal neurotransmission deficits that were manifested by reduced extracellular dopamine levels in the striatum |
| GO:0033617 mitochondrial respiratory chain complex IV assembly | ISO GO_REF:0000119 | UNDECIDED | Summary: ISO from human PNKD: mitochondrial respiratory chain complex IV assembly. Reason: The human source annotation for this term is no longer present in the current QuickGO annotation set for Q8N490 (checked 2026-10-20), and none of the cached publications describe a role of PNKD in cytochrome c oxidase assembly. I could not identify or read the original evidence, so I cannot assess whether PNKD (presumably the mitochondrial short isoform) participates in complex IV assembly or merely affects it. Supporting Evidence: PMID:21487022 there was strong support for the short isoform to be localized to mitochondria |
| GO:0042053 regulation of dopamine metabolic process | IMP PMID:22214848 Dopamine dysregulation in a mouse model of paroxysmal nonkin... | MARK AS OVER ANNOTATED | Summary: IMP: Pnkd mutant mice show altered striatal dopamine levels. Reason: The phenotype (reduced extracellular dopamine, altered release in response to caffeine and ethanol) is a release/transmission phenotype rather than evidence that Pnkd regulates dopamine synthesis or degradation. With the acts_upstream_of_or_within qualifier the claim is not false, but dopamine metabolic process overstates what was shown; the dopaminergic synaptic transmission row covers the observation. Supporting Evidence: PMID:22214848 They also showed nigrostriatal neurotransmission deficits that were manifested by reduced extracellular dopamine levels in the striatum |
| GO:0046929 negative regulation of neurotransmitter secretion | IEA GO_REF:0000120 | KEEP AS NON CORE | Summary: ARBA/Ensembl transfer from human. Reason: Overexpressed wild-type PNKD suppresses synaptic vesicle exocytosis in cultured hippocampal neurons and inhibits the RIM-dependent enhancement of release, while disease-mutant PNKD is less effective. This is the best-supported process role for Pnkd, but it rests largely on overexpression, the knockout instead shows impaired synaptic strength attributed to RIM destabilisation, and the mechanism (and whether it depends on the hydrolase activity) is unknown. Kept as a genuine but not yet mechanistically defined role; not elevated to core. Supporting Evidence: PMID:25730884 Overexpressed PNKD protein suppresses release, and mutant PNKD protein is less effective than wild-type at inhibiting exocytosis. PMID:25730884 wild-type PNKD protein inhibits the RIM-dependent increase of neurotransmitter release PMID:25730884 In PNKD KO mice, RIM1/2 protein levels are reduced and synaptic strength is impaired. |
| GO:0046929 negative regulation of neurotransmitter secretion | IGI PMID:25730884 Protein mutated in paroxysmal dyskinesia interacts with the ... | KEEP AS NON CORE | Summary: IGI: overexpressed PNKD inhibits the RIM-dependent increase in neurotransmitter release (with Rims1/Rims2). Reason: Overexpressed wild-type PNKD suppresses synaptic vesicle exocytosis in cultured hippocampal neurons and inhibits the RIM-dependent enhancement of release, while disease-mutant PNKD is less effective. This is the best-supported process role for Pnkd, but it rests largely on overexpression, the knockout instead shows impaired synaptic strength attributed to RIM destabilisation, and the mechanism (and whether it depends on the hydrolase activity) is unknown. Kept as a genuine but not yet mechanistically defined role; not elevated to core. Supporting Evidence: PMID:25730884 Overexpressed PNKD protein suppresses release, and mutant PNKD protein is less effective than wild-type at inhibiting exocytosis. PMID:25730884 wild-type PNKD protein inhibits the RIM-dependent increase of neurotransmitter release PMID:25730884 In PNKD KO mice, RIM1/2 protein levels are reduced and synaptic strength is impaired. |
| GO:0046929 negative regulation of neurotransmitter secretion | IGI PMID:25730884 Protein mutated in paroxysmal dyskinesia interacts with the ... | KEEP AS NON CORE | Summary: IGI: overexpressed PNKD inhibits the RIM-dependent increase in neurotransmitter release (with Rims1/Rims2). Reason: Overexpressed wild-type PNKD suppresses synaptic vesicle exocytosis in cultured hippocampal neurons and inhibits the RIM-dependent enhancement of release, while disease-mutant PNKD is less effective. This is the best-supported process role for Pnkd, but it rests largely on overexpression, the knockout instead shows impaired synaptic strength attributed to RIM destabilisation, and the mechanism (and whether it depends on the hydrolase activity) is unknown. Kept as a genuine but not yet mechanistically defined role; not elevated to core. Supporting Evidence: PMID:25730884 Overexpressed PNKD protein suppresses release, and mutant PNKD protein is less effective than wild-type at inhibiting exocytosis. PMID:25730884 wild-type PNKD protein inhibits the RIM-dependent increase of neurotransmitter release PMID:25730884 In PNKD KO mice, RIM1/2 protein levels are reduced and synaptic strength is impaired. |
| GO:0046929 negative regulation of neurotransmitter secretion | ISO GO_REF:0000119 | KEEP AS NON CORE | Summary: Transfer from human PNKD IMP annotation (PMID:25730884). Reason: Overexpressed wild-type PNKD suppresses synaptic vesicle exocytosis in cultured hippocampal neurons and inhibits the RIM-dependent enhancement of release, while disease-mutant PNKD is less effective. This is the best-supported process role for Pnkd, but it rests largely on overexpression, the knockout instead shows impaired synaptic strength attributed to RIM destabilisation, and the mechanism (and whether it depends on the hydrolase activity) is unknown. Kept as a genuine but not yet mechanistically defined role; not elevated to core. Supporting Evidence: PMID:25730884 Overexpressed PNKD protein suppresses release, and mutant PNKD protein is less effective than wild-type at inhibiting exocytosis. PMID:25730884 wild-type PNKD protein inhibits the RIM-dependent increase of neurotransmitter release PMID:25730884 In PNKD KO mice, RIM1/2 protein levels are reduced and synaptic strength is impaired. |
| GO:0050884 neuromuscular process controlling posture | IMP PMID:22214848 Dopamine dysregulation in a mouse model of paroxysmal nonkin... | MARK AS OVER ANNOTATED | Summary: IMP: Pnkd mutant mice recapitulate paroxysmal dyskinesia (dystonic postures). Reason: Dyskinetic attacks in knock-in mutant mice are an organismal disease phenotype of a dominant mutant allele. They show that Pnkd perturbation affects motor control, not that Pnkd participates in the neuromuscular process controlling posture. Kept only as an upstream phenotype-level association. Supporting Evidence: PMID:22214848 Transgenic mice carrying mutations in the mouse Pnkd locus equivalent to those found in patients with PNKD recapitulated the human PNKD phenotype. |
| GO:0051596 methylglyoxal catabolic process | IEA GO_REF:0000002 | REMOVE | Summary: InterPro2GO mapping from the hydroxyacylglutathione hydrolase signature. Reason: Methylglyoxal catabolism via the glyoxalase pathway requires efficient S-D-lactoylglutathione hydrolysis. The human ortholog has only trace in vitro SLG hydrolase activity and does not restore SLG metabolism in hagh-null Drosophila, so PNKD is not a glyoxalase II in vivo. This electronic mapping of a HAGH signature to the divergent PNKD subfamily is not supported; PAINT did not propagate it. Supporting Evidence: PMID:21487022 further supporting the idea that PNKD-L does not use SLG as an in vivo substrate PMID:21487022 This indicates that hydrolysis of SLG in vivo by PNKD-L is unlikely to be physiologically relevant. |
| GO:0099523 presynaptic cytosol | IDA PMID:25730884 Protein mutated in paroxysmal dyskinesia interacts with the ... | ACCEPT | Summary: IDA: immunogold EM localises endogenous Pnkd to presynaptic terminals in mouse cortex, absent in Pnkd-/-. Reason: Direct mouse evidence with knockout control. Pnkd is found in presynaptic terminals (and also postsynaptically), consistent with its binding of active-zone RIM proteins. Supporting Evidence: PMID:25730884 we show that the ultrastructural localization of PNKD includes specific presence in presynaptic terminals |
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Download this section (compressed HTML)Q: What is the physiological alpha-hydroxythioester substrate of the PNKD long isoform, and does the decrease in cortical glutathione in Pnkd-null mice reflect loss of a glutathione thioester hydrolase activity?
Q: Does the suppression of synaptic vesicle exocytosis by PNKD and its stabilisation of RIM1/RIM2 require the metallo-beta-lactamase active site, or is it a non-enzymatic scaffolding role?
Q: Which mouse isoforms are mitochondrial versus plasma membrane-associated, and is the mitochondrial complex IV assembly annotation transferred from human still supported?
Experiment: Activity-based or untargeted metabolomic substrate screen of recombinant mouse Pnkd long isoform (wild type vs H172A/H174A zinc-site mutant) against glutathione and CoA thioesters of alpha-hydroxy acids, with kinetic characterisation of hits.
Experiment: Rescue of Pnkd-/- synaptic transmission and RIM1/2 levels with wild-type versus catalytically dead Pnkd-L in cultured hippocampal neurons.
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