id: P46019
gene_symbol: PHKA2
product_type: PROTEIN
status: INITIALIZED
taxon:
  id: NCBITaxon:9606
  label: Homo sapiens
description: >-
  PHKA2 encodes the liver isoform of the alpha regulatory subunit of phosphorylase
  kinase (PhK). PhK is a large hexadecameric (alpha-beta-gamma-delta)4 holoenzyme in
  which the gamma subunit (PHKG1 in muscle, PHKG2 in liver) is the catalytic
  serine/threonine kinase and the large alpha (PHKA1/PHKA2) and beta (PHKB) subunits
  are regulatory; the delta subunit is calmodulin, conferring Ca2+ sensitivity. PHKA2
  is itself non-catalytic: as a regulatory subunit it is a target of cAMP-dependent
  (PKA) phosphorylation which, together with Ca2+/calmodulin, relieves inhibition and
  activates the catalytic gamma subunit. The activated holoenzyme phosphorylates
  glycogen phosphorylase (b to a), triggering glycogenolysis; PhK thereby couples
  hormonal and neural signals to hepatic glycogen breakdown. PHKA2 binds calmodulin
  and acts in the cytosol. Loss-of-function variants in PHKA2 cause X-linked liver
  phosphorylase kinase deficiency (glycogen storage disease type IXa, GSD9A), the most
  common form of PhK deficiency, characterized by hepatomegaly and growth retardation
  that are usually mild and improve with age.
existing_annotations:
- term:
    id: GO:0005964
    label: phosphorylase kinase complex
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  qualifier: part_of
  review:
    summary: >-
      Phylogenetically inferred membership in the phosphorylase kinase complex. This
      is the defining, core cellular-component assignment for PHKA2 as the liver alpha
      regulatory subunit of the (alpha-beta-gamma-delta)4 holoenzyme.
    action: ACCEPT
    reason: >-
      Strongly supported: PHKA2 is one of the alpha subunits of the phosphorylase
      kinase holoenzyme. UniProt SUBUNIT describes the complex composition and assigns
      alpha/beta as regulatory subunits, consistent with this IBA assignment.
    supported_by:
    - reference_id: file:human/PHKA2/PHKA2-uniprot.txt
      supporting_text: "beta, gamma, and delta subunits. Alpha (PHKA1 or PHKA2) and beta (PHKB)"
- term:
    id: GO:0004689
    label: phosphorylase kinase activity
  evidence_type: IEA
  original_reference_id: GO_REF:0000117
  qualifier: enables
  review:
    summary: >-
      ARBA electronic assertion that PHKA2 enables phosphorylase kinase activity. This
      is the activity of the holoenzyme, catalyzed by the gamma subunit (PHKG1/PHKG2);
      the alpha subunit is regulatory and non-catalytic.
    action: MARK_AS_OVER_ANNOTATED
    reason: >-
      The catalytic phosphorylase kinase activity resides in the gamma subunit, not the
      alpha regulatory subunit. UniProt states that alpha and beta are regulatory
      subunits while gamma is the catalytic subunit, so an 'enables' assertion of the
      holoenzyme kinase activity on PHKA2 over-attributes catalysis to a regulatory
      chain. PHKA2 contributes to this holoenzyme activity as a complex member (captured
      in core_functions via contributes_to_molecular_function) but does not
      independently enable it.
    supported_by:
    - reference_id: file:human/PHKA2/PHKA2-uniprot.txt
      supporting_text: "are regulatory subunits, gamma (PHKG1 or PHKG2) is the catalytic"
- term:
    id: GO:0005516
    label: calmodulin binding
  evidence_type: IEA
  original_reference_id: GO_REF:0000002
  qualifier: enables
  review:
    summary: >-
      InterPro-based assertion of calmodulin binding. This is a genuine molecular
      function of the alpha subunit: UniProt notes the alpha chain may bind calmodulin
      and annotates two calmodulin-binding regions (807-837, 1059-1099).
    action: ACCEPT
    reason: >-
      Well supported and biologically informative for the alpha subunit. Consistent
      with the Calmodulin-binding keyword and two annotated calmodulin-binding regions.
      Calmodulin is the delta subunit of the complex, so alpha-CaM binding is
      functionally central to Ca2+ regulation of the holoenzyme.
    supported_by:
    - reference_id: file:human/PHKA2/PHKA2-uniprot.txt
      supporting_text: "The alpha chain may"
    - reference_id: file:human/PHKA2/PHKA2-uniprot.txt
      supporting_text: "bind calmodulin."
- term:
    id: GO:0005737
    label: cytoplasm
  evidence_type: IEA
  original_reference_id: GO_REF:0000117
  qualifier: located_in
  review:
    summary: >-
      ARBA electronic assertion of cytoplasmic localization. Correct but non-specific;
      the more precise, curatorially supported location is the cytosol (GO:0005829).
    action: ACCEPT
    reason: >-
      Cytoplasm is a correct broad parent of the cytosol, where the phosphorylase
      kinase complex acts on cytosolic glycogen phosphorylase. Retained as a valid,
      if less specific, location; the cytosol annotation is the more informative one.
- term:
    id: GO:0005886
    label: plasma membrane
  evidence_type: IEA
  original_reference_id: GO_REF:0000044
  qualifier: located_in
  review:
    summary: >-
      Subcellular-location keyword mapping (SL-0039) derived from UniProt's Cell
      membrane assignment, which is itself an ECO:0000305 (inference from prenylation)
      annotation, not an experimental localization.
    action: MARK_AS_OVER_ANNOTATED
    reason: >-
      The UniProt Cell membrane / Lipid-anchor location is an ECO:0000305 inference
      resting on a possible C-terminal farnesyl-cysteine (itself by-similarity,
      ECO:0000250), with the PTM note stating the terminal tripeptide is 'probably not
      removed'. The functionally relevant and better-supported compartment is the
      cytosol, where the complex phosphorylates cytosolic glycogen phosphorylase.
      Retained but flagged as a weakly supported, likely over-annotated location.
    supported_by:
    - reference_id: file:human/PHKA2/PHKA2-uniprot.txt
      supporting_text: "SUBCELLULAR LOCATION: Cell membrane"
- term:
    id: GO:0005975
    label: carbohydrate metabolic process
  evidence_type: IEA
  original_reference_id: GO_REF:0000002
  qualifier: involved_in
  review:
    summary: >-
      InterPro-based involvement in carbohydrate metabolism. Correct but broad; PHKA2
      participates specifically in glycogen catabolism as part of the phosphorylase
      kinase complex.
    action: ACCEPT
    reason: >-
      Accurate high-level biological-process assignment. The more specific glycogen
      metabolic / glycogen catabolic terms better capture the function and are
      reflected in core_functions, but this broad parent is not incorrect.
- term:
    id: GO:0005977
    label: glycogen metabolic process
  evidence_type: IEA
  original_reference_id: GO_REF:0000120
  qualifier: involved_in
  review:
    summary: >-
      Combined-IEA/UniPathway involvement in glycogen metabolism. Accurate: the
      phosphorylase kinase complex regulates hepatic glycogenolysis, and PHKA2
      deficiency causes a glycogen storage disease.
    action: ACCEPT
    reason: >-
      Well aligned with the gene's biology. UniProt PATHWAY records glycogen
      metabolism, and PHKA2 loss-of-function causes glycogen storage disease type IXa.
      The catabolic direction is captured more specifically in core_functions.
    supported_by:
    - reference_id: file:human/PHKA2/PHKA2-uniprot.txt
      supporting_text: "PATHWAY: Glycan biosynthesis; glycogen metabolism."
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:23455922
  qualifier: enables
  review:
    summary: >-
      Bare protein-binding annotation from a large-scale AP-MS protein-complex
      interlaboratory reproducibility study. Uninformative term with no specific,
      functionally interpreted partner recorded.
    action: MARK_AS_OVER_ANNOTATED
    reason: >-
      'Protein binding' (GO:0005515) is an uninformative molecular-function term. The
      supporting reference is a high-throughput interactome dataset that does not
      characterize a specific PHKA2 function; the biologically meaningful partners
      (PHKG2, PHKB) are already captured by the phosphorylase kinase complex
      annotation. Per curation policy this experimental IPI is marked as
      over-annotated rather than removed.
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:26496610
  qualifier: enables
  review:
    summary: >-
      Bare protein-binding annotation from a quantitative human-interactome study.
      Uninformative term with no specific functional partner recorded.
    action: MARK_AS_OVER_ANNOTATED
    reason: >-
      Uninformative 'protein binding' term derived from a large-scale interactome
      dataset. No specific PHKA2 function is established. Marked as over-annotated per
      curation policy rather than removed.
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:28514442
  qualifier: enables
  review:
    summary: >-
      Bare protein-binding annotation from a large-scale interactome/protein-community
      study. Uninformative term.
    action: MARK_AS_OVER_ANNOTATED
    reason: >-
      Uninformative 'protein binding' term from a high-throughput interactome dataset;
      no specific PHKA2 molecular function is established. Marked over-annotated per
      policy rather than removed.
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:32296183
  qualifier: enables
  review:
    summary: >-
      Bare protein-binding annotation from a binary (Y2H) reference-interactome map.
      Uninformative term.
    action: MARK_AS_OVER_ANNOTATED
    reason: >-
      Uninformative 'protein binding' term from a large-scale binary interactome
      screen. No specific, functionally interpreted PHKA2 partner is captured beyond
      complex membership already annotated elsewhere. Marked over-annotated per policy.
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:32707033
  qualifier: enables
  review:
    summary: >-
      Bare protein-binding annotation from a kinase-interaction-network study. The
      relevant kinase partner (PHKG2, the catalytic gamma subunit) reflects complex
      membership, but the bare term itself is uninformative.
    action: MARK_AS_OVER_ANNOTATED
    reason: >-
      Uninformative 'protein binding' term. The functionally meaningful interaction
      (with the catalytic gamma subunit PHKG2) is captured by the phosphorylase kinase
      complex annotation; the bare MF term adds nothing. Marked over-annotated per
      policy rather than removed.
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:32814053
  qualifier: enables
  review:
    summary: >-
      Bare protein-binding annotation from a neurodegenerative-disease interactome
      mapping study (partner SPRED1). Uninformative term.
    action: MARK_AS_OVER_ANNOTATED
    reason: >-
      Uninformative 'protein binding' term from a high-throughput interactome dataset;
      the SPRED1 interaction is not functionally interpreted for PHKA2. Marked
      over-annotated per policy rather than removed.
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:33961781
  qualifier: enables
  review:
    summary: >-
      Bare protein-binding annotation from a proteome-scale, cell-specific interactome
      study. Uninformative term.
    action: MARK_AS_OVER_ANNOTATED
    reason: >-
      Uninformative 'protein binding' term from a large-scale interactome dataset; no
      specific PHKA2 function is established. Marked over-annotated per policy.
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:35271311
  qualifier: enables
  review:
    summary: >-
      Bare protein-binding annotation from the OpenCell endogenous-tagging cellular
      cartography study. Uninformative term.
    action: MARK_AS_OVER_ANNOTATED
    reason: >-
      Uninformative 'protein binding' term from a high-throughput cellular-organization
      dataset; no specific PHKA2 molecular function is established. Marked over-annotated
      per policy rather than removed.
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:40205054
  qualifier: enables
  review:
    summary: >-
      Bare protein-binding annotation from a multimodal cell-maps structural/functional
      genomics study. Uninformative term.
    action: MARK_AS_OVER_ANNOTATED
    reason: >-
      Uninformative 'protein binding' term from a large-scale cell-mapping dataset; no
      specific PHKA2 function is established. Marked over-annotated per policy rather
      than removed.
- term:
    id: GO:0005964
    label: phosphorylase kinase complex
  evidence_type: IEA
  original_reference_id: GO_REF:0000107
  qualifier: part_of
  review:
    summary: >-
      Ensembl-Compara orthology transfer of experimentally verified phosphorylase
      kinase complex membership. Consistent with the core complex assignment.
    action: ACCEPT
    reason: >-
      Correct and well supported; the same defining complex membership as the IBA and
      TAS annotations. PHKA2 is the liver alpha regulatory subunit of the holoenzyme.
    supported_by:
    - reference_id: file:human/PHKA2/PHKA2-uniprot.txt
      supporting_text: "Hexadecamer of 4 heterotetramers, each composed of alpha,"
- term:
    id: GO:0005829
    label: cytosol
  evidence_type: TAS
  original_reference_id: Reactome:R-HSA-71588
  qualifier: located_in
  review:
    summary: >-
      Reactome-curated cytosolic localization. The cytosolic phosphorylase kinase
      complex phosphorylates cytosolic glycogen phosphorylase (PYGL) in liver. This is
      the core, functionally relevant location for PHKA2.
    action: ACCEPT
    reason: >-
      Well supported by Reactome curation of the hepatic glycogenolysis reaction; the
      complex containing PHKA2 acts in the cytosol. This is the preferred location over
      the by-similarity plasma-membrane assignment.
- term:
    id: GO:0004689
    label: phosphorylase kinase activity
  evidence_type: TAS
  original_reference_id: PMID:7549948
  qualifier: enables
  review:
    summary: >-
      Author-statement (TAS) assignment of phosphorylase kinase activity from the paper
      cloning the human liver PHKA2 alpha subunit. The described activity is that of the
      PhK holoenzyme, catalyzed by the gamma subunit; the alpha subunit is regulatory.
    action: MARK_AS_OVER_ANNOTATED
    reason: >-
      The cited paper isolates and characterizes the liver alpha subunit and discusses
      liver phosphorylase kinase (the holoenzyme), but the catalytic activity resides in
      the gamma subunit. Assigning 'enables phosphorylase kinase activity' to the
      regulatory alpha subunit over-attributes catalysis. PHKA2 contributes to this
      holoenzyme activity as a complex member (contributes_to_molecular_function in
      core_functions) but does not independently enable it.
    supported_by:
    - reference_id: PMID:7549948
      supporting_text: "We isolated and determined the structure of human liver alpha subunit of PHK (PHKA2) cDNA."
- term:
    id: GO:0005964
    label: phosphorylase kinase complex
  evidence_type: TAS
  original_reference_id: PMID:7549948
  qualifier: part_of
  review:
    summary: >-
      Author-statement (TAS) assignment of phosphorylase kinase complex membership from
      the paper cloning the human liver PHKA2 alpha subunit. Core complex membership.
    action: ACCEPT
    reason: >-
      Directly supported: the reference characterizes PHKA2 as the human liver alpha
      subunit of phosphorylase kinase, establishing its membership in the holoenzyme
      complex.
    supported_by:
    - reference_id: PMID:7549948
      supporting_text: "We isolated and determined the structure of human liver alpha subunit of PHK (PHKA2) cDNA."
- term:
    id: GO:0005975
    label: carbohydrate metabolic process
  evidence_type: TAS
  original_reference_id: PMID:7549948
  qualifier: involved_in
  review:
    summary: >-
      Author-statement involvement in carbohydrate metabolism. Correct but broad; the
      specific process is glycogen catabolism via the phosphorylase kinase complex.
    action: ACCEPT
    reason: >-
      Accurate high-level assignment supported by the paper's framing of PHKA2 in liver
      glycogenosis. More specific glycogen catabolic terms are captured in
      core_functions, but this broad parent is not incorrect.
    supported_by:
    - reference_id: PMID:7549948
      supporting_text: "deficiency is the most frequent liver glycogen storage disease."
- term:
    id: GO:0006091
    label: generation of precursor metabolites and energy
  evidence_type: TAS
  original_reference_id: PMID:7549948
  qualifier: involved_in
  review:
    summary: >-
      Author-statement involvement in generation of precursor metabolites and energy.
      This reflects the downstream role of hepatic glycogenolysis in supplying glucose
      for energy, an indirect/downstream consequence rather than PHKA2's core function.
    action: KEEP_AS_NON_CORE
    reason: >-
      Glycogenolysis driven by the phosphorylase kinase complex ultimately supplies
      glucose for energy metabolism, so this term is defensible but represents a
      downstream physiological role rather than the core molecular/complex function of
      the regulatory alpha subunit. Retained as non-core.
- term:
    id: GO:0036211
    label: protein modification process
  evidence_type: TAS
  original_reference_id: PMID:7549948
  qualifier: involved_in
  review:
    summary: >-
      Author-statement involvement in protein modification process, referring to PhK's
      phosphorylation of its substrate (glycogen phosphorylase). This is a property of
      the catalytic gamma subunit and is an over-broad, over-attributed term for the
      regulatory alpha subunit.
    action: MARK_AS_OVER_ANNOTATED
    reason: >-
      Protein modification is what the holoenzyme's catalytic gamma subunit does
      (phosphorylating glycogen phosphorylase); assigning it to the non-catalytic alpha
      regulatory subunit both over-attributes the activity and is uninformatively broad.
      Marked as over-annotated.
    supported_by:
    - reference_id: file:human/PHKA2/PHKA2-uniprot.txt
      supporting_text: "Phosphorylase b kinase catalyzes the phosphorylation of"
- term:
    id: GO:0005980
    label: glycogen catabolic process
  evidence_type: TAS
  original_reference_id: Reactome:R-HSA-71588
  qualifier: involved_in
  review:
    summary: >-
      Proposed specific biological-process annotation: as a subunit of the cytosolic
      phosphorylase kinase complex, PHKA2 participates in glycogen catabolism (the
      complex phosphorylates glycogen phosphorylase to trigger glycogenolysis).
    action: NEW
    reason: >-
      Captures the specific catabolic direction of PHKA2's glycogen-metabolic role,
      more precise than the existing carbohydrate/glycogen metabolic process
      annotations. Supported by Reactome curation of the hepatic glycogenolysis
      reaction catalyzed by the PhK complex containing PHKA2, and by the gene's
      loss-of-function disease (GSD IXa, a liver glycogenosis).
    supported_by:
    - reference_id: PMID:7549948
      supporting_text: "deficiency is the most frequent liver glycogen storage disease."
core_functions:
- description: >-
    As the liver alpha regulatory subunit, PHKA2 binds calmodulin (the delta subunit)
    and is a component of the phosphorylase kinase holoenzyme, contributing to its
    Ca2+- and phosphorylation-regulated phosphorylase kinase activity while being itself
    non-catalytic. Through the complex it drives cytosolic glycogen catabolism.
  molecular_function:
    id: GO:0005516
    label: calmodulin binding
  contributes_to_molecular_function:
    id: GO:0004689
    label: phosphorylase kinase activity
  directly_involved_in:
  - id: GO:0005980
    label: glycogen catabolic process
  in_complex:
    id: GO:0005964
    label: phosphorylase kinase complex
  locations:
  - id: GO:0005829
    label: cytosol
  supported_by:
  - reference_id: file:human/PHKA2/PHKA2-uniprot.txt
    supporting_text: "are regulatory subunits, gamma (PHKG1 or PHKG2) is the catalytic"
  - reference_id: file:human/PHKA2/PHKA2-uniprot.txt
    supporting_text: "The alpha chain may"
  - reference_id: PMID:7549948
    supporting_text: "deficiency is the most frequent liver glycogen storage disease."
proposed_new_terms: []
suggested_questions:
- question: >-
    Does the C-terminal cysteine of PHKA2 undergo farnesylation in vivo, and if so, does
    it target a fraction of the complex to membranes, or is the functionally dominant
    pool cytosolic?
- question: >-
    Which specific PKA (and autocatalytic) phosphorylation sites on the PHKA2 alpha
    subunit mediate activation of the holoenzyme, and how do GSD9A missense variants
    perturb this regulation versus simply destabilizing the complex?
suggested_experiments:
- description: >-
    Reconstitute the liver holoenzyme with wild-type versus GSD9A-variant PHKA2 and
    measure Ca2+/calmodulin- and PKA-phosphorylation-dependent activation of glycogen
    phosphorylase to distinguish assembly defects from regulatory defects.
- description: >-
    Determine the subcellular distribution of endogenous PHKA2 in hepatocytes (cytosol
    versus membrane) and test whether inhibiting prenylation redistributes the complex.
references:
- id: GO_REF:0000002
  title: Gene Ontology annotation through association of InterPro records with GO
    terms
  findings: []
- id: GO_REF:0000033
  title: Annotation inferences using phylogenetic trees
  findings: []
- id: GO_REF:0000044
  title: Gene Ontology annotation based on UniProtKB/Swiss-Prot Subcellular Location
    vocabulary mapping, accompanied by conservative changes to GO terms applied by
    UniProt
  findings: []
- id: GO_REF:0000107
  title: Automatic transfer of experimentally verified manual GO annotation data to
    orthologs using Ensembl Compara
  findings: []
- id: GO_REF:0000117
  title: Electronic Gene Ontology annotations created by ARBA machine learning models
  findings: []
- id: GO_REF:0000120
  title: Combined Automated Annotation using Multiple IEA Methods
  findings: []
- id: file:human/PHKA2/PHKA2-uniprot.txt
  title: UniProtKB entry P46019 (KPB2_HUMAN), Phosphorylase b kinase regulatory subunit
    alpha, liver isoform
  findings: []
- id: PMID:23455922
  title: Interlaboratory reproducibility of large-scale human protein-complex analysis
    by standardized AP-MS.
  findings: []
  reference_review:
    relevance: LOW
    correctness: VERIFIED
    review_notes: >-
      High-throughput AP-MS dataset underpinning a bare protein-binding IPI; no
      PHKA2-specific function established.
- id: PMID:26496610
  title: A human interactome in three quantitative dimensions organized by stoichiometries
    and abundances.
  findings: []
  reference_review:
    relevance: LOW
    correctness: VERIFIED
    review_notes: >-
      Large-scale quantitative interactome dataset; source of a bare protein-binding IPI.
- id: PMID:28514442
  title: Architecture of the human interactome defines protein communities and disease
    networks.
  findings: []
  reference_review:
    relevance: LOW
    correctness: VERIFIED
    review_notes: >-
      Large-scale interactome/community dataset; source of a bare protein-binding IPI.
- id: PMID:32296183
  title: A reference map of the human binary protein interactome.
  findings: []
  reference_review:
    relevance: LOW
    correctness: VERIFIED
    review_notes: >-
      Binary (Y2H) reference-interactome dataset; source of bare protein-binding IPIs.
- id: PMID:32707033
  title: Kinase Interaction Network Expands Functional and Disease Roles of Human
    Kinases.
  findings: []
  reference_review:
    relevance: LOW
    correctness: VERIFIED
    review_notes: >-
      Kinase-interaction-network dataset; the meaningful partner (catalytic gamma
      subunit PHKG2) reflects complex membership already captured elsewhere.
- id: PMID:32814053
  title: Interactome Mapping Provides a Network of Neurodegenerative Disease Proteins
    and Uncovers Widespread Protein Aggregation in Affected Brains.
  findings: []
  reference_review:
    relevance: LOW
    correctness: VERIFIED
    review_notes: >-
      Neurodegenerative-disease interactome dataset; source of a bare protein-binding
      IPI (SPRED1), not functionally interpreted for PHKA2.
- id: PMID:33961781
  title: Dual proteome-scale networks reveal cell-specific remodeling of the human
    interactome.
  findings: []
  reference_review:
    relevance: LOW
    correctness: VERIFIED
    review_notes: >-
      Proteome-scale interactome dataset; source of a bare protein-binding IPI.
- id: PMID:35271311
  title: 'OpenCell: Endogenous tagging for the cartography of human cellular organization.'
  findings: []
  reference_review:
    relevance: LOW
    correctness: VERIFIED
    review_notes: >-
      Endogenous-tagging cellular-organization dataset; source of a bare protein-binding
      IPI.
- id: PMID:40205054
  title: Multimodal cell maps as a foundation for structural and functional genomics.
  findings: []
  reference_review:
    relevance: LOW
    correctness: VERIFIED
    review_notes: >-
      Multimodal cell-mapping dataset; source of a bare protein-binding IPI.
- id: PMID:7549948
  title: Isolation of cDNA encoding the human liver phosphorylase kinase alpha subunit
    (PHKA2) and identification of a missense mutation of the PHKA2 gene in a family
    with liver phosphorylase kinase deficiency.
  findings: []
  reference_review:
    relevance: HIGH
    correctness: VERIFIED
    review_notes: >-
      Abstract-only cache. Directly establishes PHKA2 as the human liver alpha subunit
      of phosphorylase kinase and links it to X-linked liver PhK deficiency (GSD IXa);
      basis for the TAS complex/activity/process annotations.
- id: Reactome:R-HSA-71588
  title: glycogen phosphorylase (PYGL) dimer b + 2 ATP => glycogen phosphorylase (PYGL)
    dimer a + 2 ADP
  findings: []