Annotation inferences using phylogenetic trees
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The PAINT record for PTHR43173 has exactly one annotated node, PTN005148758, carrying exactly three terms, all seeded from SGD:S000004243 (yeast MCP2/Cqd2). The node's reach is 97 entities, identical for all three terms. No molecular-function term is asserted at the node, so PAINT did not propagate any kinase activity into this family.
Gene Ontology annotation based on UniProtKB/Swiss-Prot Subcellular Location vocabulary mapping, accompanied by conservative changes to GO terms applied by UniProt
Drosophila ADCK1 is critical for maintaining mitochondrial structures and functions in the muscle.
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Human HeLa siRNA knockdown of ADCK1, assayed by transmission electron microscopy, increased mitochondrial length and decreased cristae number - the direct human basis for both IMP rows, despite the paper's Drosophila-focused title.
"As a result, the mitochondrial length was increased and the number of mitochondrial cristae was decreased by ADCK1 knockdown"
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Co-expression of ADCK1 with OPA1 in HEK293T cells increased cleavage of long-form OPA1, quantified across four replicates - the biochemical step underlying the morphological phenotypes, and the basis of the proposed GO:0010954 annotation.
"The result demonstrated that the over-expression of both OPA1 and ADCK1 led to increased cleavage of L-OPA1"
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Kinase-dead substitutions at the phosphotransfer residues did not abolish the phenotypes caused by ADCK1 over-expression. The scope of this result is gain-of-function: it shows the over-expression phenotype does not require these residues, not that ADCK1 lacks activity.
"Over-expression of each mutant as well as the triple-mutation-containing form (K183I-D315A-D338N; 3KD) of ADCK1 still induced the same phenotypes similar to ADCK1 wild type, and thus we concluded that the phenotypes induced by ADCK1 are kinase-independent"
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The authors state the prior explicitly rather than claiming a negative: at the time of writing no report confirmed that ADCK1 is a kinase. No in vitro assay of purified ADCK1 has been published since.
"Until now, ADCK1 was predicted to be a kinase, yet there were no available reports to confirm it."
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Knockdown of dYME1L1 rescued the pupal lethality of dADCK1 over-expression, placing ADCK1 genetically upstream of YME1L1. The relationship is epistatic; no physical ADCK1-YME1L1 interaction is reported.
"the flies over-expressing dADCK1 with simultaneous dYME1L1 knockdown successfully survived into adulthood"
A subcellular map of the human kinome.
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Localisation was determined by imaging epitope-tagged kinases ectopically expressed in HeLa cells. This is the assay behind the GO:0005739 IDA and behind UniProt's SUBCELLULAR LOCATION line; the over-expression caveat is recorded, and two independent measurements agree with the result.
"456 epitope-tagged kinases, representing 85% of the human kinome, were expressed in HeLa cells and imaged by immunofluorescent microscopy"
Quantitative high-confidence human mitochondrial proteome and its dynamics in cellular context.
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A purpose-built high-confidence human mitochondrial proteome; ADCK1 is among the proteins for which the paper lists a validating antibody, so its inclusion is not a pure MS assignment. The reference carries 1235 GO annotations, but no functional or phenotype term spreads with the localisation term, so this is per-protein measurement rather than a projection.
FOXQ1 Regulates Brain Endothelial Mitochondrial Function by Orchestrating Calcium Signaling and Cristae Morphology.
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Mouse ADCK1 was localised directly to the mitochondrial inner membrane in primary brain endothelial cells - independent mammalian corroboration of the compartment that human ADCK1 holds only by IBA.
"We first confirmed that mouse ADCK1 was localized to the mitochondrial inner membrane in primary brain ECs"
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ADCK1 co-immunoprecipitates with IMMT, the MICOS core subunit that forms crista junctions, in primary brain endothelial cells.
"Co‐IP assay detecting interaction between ADCK1 and IMMT in primary brain ECs"
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ADCK1 over-expression increases and Adck1 knockdown decreases cleavage of long-form OPA1 in mouse primary brain endothelial cells - a bidirectional replication, in a second organism and a second laboratory, of the OPA1-processing result first reported in HEK293T cells.
"Immunoblot images showing the levels of OPA1 in primary bECs infected with OPA1‐Flag and with either the empty vector, ADCK1‐HA, or Adck1‐shRNA lentivirus."
Mitochondrial ADCK3 employs an atypical protein kinase-like fold to enable coenzyme Q biosynthesis.
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Defines the UbiB-specific structural features from the ADCK3/COQ8A crystal structure, including the alanine-rich loop that selects ADP over ATP. ADCK1's A164 occupies the same loop position as the ADCK3 A339 mutated here, which is why the ATP ligand assigned to ADCK1's binding sites by ProRule is questionable.
"We find that multiple UbiB-specific features are poised to inhibit protein kinase activity, including an N-terminal domain that occupies the typical substrate binding pocket and a unique A-rich loop that limits ATP binding by establishing an unusual selectivity for ADP."
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The single ADCK3 A339G substitution reverses coenzyme selectivity and permits autophosphorylation, establishing that the alanine-rich loop is a functional determinant rather than an incidental sequence feature.
"A single alanine-to-glycine mutation of this loop flips this coenzyme selectivity and enables autophosphorylation but inhibits coenzyme Q biosynthesis in vivo"
Cerebellar Ataxia and Coenzyme Q Deficiency through Loss of Unorthodox Kinase Activity.
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COQ8 lacks canonical protein-kinase activity in trans but has ATPase activity and binds lipid coenzyme-Q intermediates. This is the experimental basis of the GO:0004672 NOT|enables and GO:0006468 NOT|involved_in IDA rows on both COQ8A and COQ8B. It is the main basis for doubting the serine/threonine-kinase keyword on ADCK1, though not on its own: an ancestrally reconstructed COQ8B was later shown to phosphorylate a protein substrate in trans (PMID:38425362), so the family-level claim that survives is the narrower one that no UbiB protein has been typed as a Ser/Thr kinase.
"Although COQ8 was predicted to be a protein kinase, we demonstrate that it lacks canonical protein kinase activity in trans. Instead, COQ8 has ATPase activity and interacts with lipid CoQ intermediates"
In vitro construction of the COQ metabolon unveils the molecular determinants of coenzyme Q biosynthesis.
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The single demonstration of protein-kinase activity anywhere in the UbiB family, and the source of COQ8B's non-negated GO:0004672 IDA: COQ8B phosphorylates COQ3 in trans. Two limits on how far it reaches - the enzyme is an ancestral reconstruction rather than the extant human protein, and the residue class was not determined, so it does not establish Ser/Thr specificity for any UbiB protein. It also sits alongside COQ8B's own NOT|enables GO:0004672 row from PMID:27499294, which the two annotations leave unreconciled.
"Intact protein MS validated this idea: COQ3, but not COQ6, is phosphorylated by COQ8B at multiple sites"
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The COQ8B used throughout the study is an ancestrally reconstructed protein, purified because ancestral COQ8A gave poor yields. The paper does not state that it reverted to extant human COQ8B for the phosphorylation experiment.
"Ancestral COQ8A and COQ8B were purified as membrane-bound recombinant proteins; however, COQ8A produced very low yields compared with COQ8B."
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The same work excludes small-molecule kinase activity for COQ8B, so its phosphotransfer output is protein-directed rather than directed at the CoQ intermediates it binds.
"Critically, GC/MS analyses did not detect any phosphorylated CoQ intermediates, suggesting that the enzyme is not a small-molecule kinase."
UbiB proteins regulate cellular CoQ distribution in Saccharomyces cerevisiae.
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Renames yeast Mcp2/Ylr253w as Cqd2 and shows that its loss shifts coenzyme Q distribution in the direction opposite to loss of Cqd1. Cqd2 is the sole protein donor behind all three of ADCK1's IBA rows, so this is the best-characterised activity of the source of those transfers.
"Loss of Cqd1 skews cellular CoQ distribution away from mitochondria, resulting in markedly enhanced resistance to oxidative stress caused by exogenous polyunsaturated fatty acids, whereas loss of Cqd2 promotes the opposite effects."
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The phenotype is one of distribution, not synthesis - total cellular CoQ is unchanged. This is why no GO:0006744 ubiquinone-biosynthesis annotation is proposed for ADCK1.
"Total cellular CoQ levels remained unchanged (Supplementary Fig. 3b), again suggesting these CoQ-related phenotypes are unrelated to CoQ biosynthesis."
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Cqd2 function requires intact canonical protein-kinase-like and UbiB-specific residues. This is the direct counterweight to the kinase-independence result reported for ADCK1 in animals, and the reason this review declines to call ADCK1 catalytically dead.
"Similar to Cqd1 (Fig. 3g), Cqd2 function was dependent on intact canonical PKL and UbiB-specific residues"
Mcp1 and Mcp2, two novel proteins involved in mitochondrial lipid homeostasis.
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The source publication for all three of MCP2's own experimental annotations (GO:0005743 IDA, GO:0007005 IMP and IGI, GO:0055088 IGI) and therefore the ultimate evidence behind ADCK1's three IBA rows. The lipid-homeostasis result comes from high-copy suppression of an mdm10 deletion, which is why that row is kept as non-core rather than as core.
"Lipid analysis demonstrates that elevated levels of Mcp1 and Mcp2 restore the alterations in mitochondrial phospholipid and ergosterol homeostasis in cells lacking Mdm10."
ADCK1 is a potential therapeutic target of osteosarcoma.
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ADCK1 depletion in osteosarcoma cells lowers mitochondrial membrane potential and ATP and raises reactive oxygen species, consistent with the mitochondrial role established elsewhere. Adds a disease context but no new function, and produces no GO annotation.
"ADCK1 depletion disrupted mitochondrial functions in OS cells and induced mitochondrial membrane potential reduction, ATP depletion, reactive oxygen species production."
ADCK1 activates the β-catenin/TCF signaling pathway to promote the growth and migration of colon cancer cells.
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Reports an endogenous co-immunoprecipitation of ADCK1 with the transcription factor TCF4 in colon cancer cells. The paper reports no experiment placing ADCK1 outside mitochondria, while three independent studies place it inside them and the protein has a mitochondrial transit peptide. Single laboratory, unreplicated; no GO annotation derives from it and none is proposed.
"the endogenous Co-IP experiment showed that endogenous ADCK1 and TCF4 formed a complex"
Affinage mechanistic annotation for ADCK1 (human)
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Machine-generated provider record, gates_passed True, five citations, all numeric PMIDs with no bioRxiv identifiers in PMID-shaped fields. Its contribution to this review was bibliographic: it surfaced PMID:40884816, PMID:36371387, PMID:33824271 and PMID:31175694, none of which is cited by any GOA row, and the first of those turned out to carry the only independent mammalian localisation and OPA1-processing data for ADCK1.
UniProt entry Q86TW2 (ADCK1_HUMAN)
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The entry asserts EC=2.7.-.-, the keywords Kinase, Serine/threonine-protein kinase, ATP-binding and Transferase, and ATP-ligand BINDING sites at 161..169 and 183 - all from PROSITE-ProRule:PRU00159 by ECO:0000255 - while its FUNCTION comment states that it is not known whether ADCK1 has protein kinase activity or what class of residue it would phosphorylate. The keyword-derived GO:0004674 and GO:0005524 cross-references are no longer present in GOA.
"EC=2.7.-.- {ECO:0000255|PROSITE-ProRule:PRU00159};"
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The three mutagenesis entries record the same gain-of-function result reported by Yoon et al.: substituting the phosphotransfer residues has no effect on the protein's role in maintaining mitochondrial structure and function.
"/note="K->I: No effect on role in maintaining mitochondrial"
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SUBCELLULAR LOCATION is experimentally grounded but resolves only to the organelle, which is what GO_REF:0000044 then maps to GO:0005739.
"CC -!- SUBCELLULAR LOCATION: Mitochondrion {ECO:0000269|PubMed:33988507}."
ADCK1: which protein-kinase catalytic motifs does it actually retain?
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ADCK1 retains all four core phosphotransfer residues (K183, D315, N320, D338), conserved in 8 of 8 UbiB proteins examined, so a pseudokinase reading based on lost catalytic residues is refused by measurement.
"All four core catalytic residues are canonical in **8/8** of the UbiB"
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ADCK1 carries the two UbiB diagnostics: an alanine-rich phosphate-binding loop retaining 1 of 3 canonical glycines, with A164 in the same column as the COQ8A ADP/ATP-selectivity determinant A339, and no catalytic-loop arginine in 0 of 8 UbiB proteins against the PKA control.
"ADCK1 retains **1/3** of the canonical glycines."