Abnormal wing discs encodes a nucleoside diphosphate kinase that maintains nucleotide triphosphate pools by transferring phosphate through a phosphohistidine intermediate. The native 168-residue PC/PD protein contains the complete 153-residue characterized enzyme sequence with an N-terminal extension. All mapped substrate-binding residues and the catalytic histidine are retained. Its core nucleotide-interconversion activity supports cellular growth and development. Awd also supports endocytic trafficking and early-endosome maturation, enabling the proper handling of signaling receptors such as Notch.
Summary: Purified Drosophila awd protein has nucleoside diphosphate kinase activity.
Reason: Purified Drosophila awd protein has nucleoside diphosphate kinase activity. The selected longer product preserves its complete sequence, catalytic histidine and nucleotide-binding residues, supporting the same nucleotide-interconversion mechanism. The N-terminal initiation disagreement does not contradict preservation of the catalytic core.
We purified the nucleoside diphosphate kinases from wild-type and mutant larvae by a simple procedure involving affinity chromatography on blue Sepharose.
file:DROME/awd/awd-reference-P08879-uniprot.txt
The ATP gamma phosphate is transferred to the NDP beta CC phosphate via a ping-pong mechanism, using a phosphorylated active-site CC intermediate.
file:DROME/awd/awd-bioinformatics/RESULTS.md
Catalytic His119 maps to target His134; all seven annotated nucleotide-binding positions are preserved.
Summary: Nucleoside diphosphate kinase supplies the corresponding nucleotide triphosphate by phosphate transfer to its diphosphate precursor.
Reason: Nucleoside diphosphate kinase supplies the corresponding nucleotide triphosphate by phosphate transfer to its diphosphate precursor. The selected product preserves the experimentally characterized enzyme core and nucleotide-binding residues, making this broad nucleotide-pool contribution a justified mechanistic transfer rather than an independent substrate-specific experiment on PC/PD.
We purified the nucleoside diphosphate kinases from wild-type and mutant larvae by a simple procedure involving affinity chromatography on blue Sepharose.
file:DROME/awd/awd-reference-P08879-uniprot.txt
The ATP gamma phosphate is transferred to the NDP beta CC phosphate via a ping-pong mechanism, using a phosphorylated active-site CC intermediate.
file:DROME/awd/awd-bioinformatics/RESULTS.md
Catalytic His119 maps to target His134; all seven annotated nucleotide-binding positions are preserved.
Summary: Nucleoside diphosphate kinase supplies the corresponding nucleotide triphosphate by phosphate transfer to its diphosphate precursor.
Reason: Nucleoside diphosphate kinase supplies the corresponding nucleotide triphosphate by phosphate transfer to its diphosphate precursor. The selected product preserves the experimentally characterized enzyme core and nucleotide-binding residues, making this broad nucleotide-pool contribution a justified mechanistic transfer rather than an independent substrate-specific experiment on PC/PD.
We purified the nucleoside diphosphate kinases from wild-type and mutant larvae by a simple procedure involving affinity chromatography on blue Sepharose.
file:DROME/awd/awd-reference-P08879-uniprot.txt
The ATP gamma phosphate is transferred to the NDP beta CC phosphate via a ping-pong mechanism, using a phosphorylated active-site CC intermediate.
file:DROME/awd/awd-bioinformatics/RESULTS.md
Catalytic His119 maps to target His134; all seven annotated nucleotide-binding positions are preserved.
Summary: Nucleoside diphosphate kinase supplies the corresponding nucleotide triphosphate by phosphate transfer to its diphosphate precursor.
Reason: Nucleoside diphosphate kinase supplies the corresponding nucleotide triphosphate by phosphate transfer to its diphosphate precursor. The selected product preserves the experimentally characterized enzyme core and nucleotide-binding residues, making this broad nucleotide-pool contribution a justified mechanistic transfer rather than an independent substrate-specific experiment on PC/PD.
We purified the nucleoside diphosphate kinases from wild-type and mutant larvae by a simple procedure involving affinity chromatography on blue Sepharose.
file:DROME/awd/awd-reference-P08879-uniprot.txt
The ATP gamma phosphate is transferred to the NDP beta CC phosphate via a ping-pong mechanism, using a phosphorylated active-site CC intermediate.
file:DROME/awd/awd-bioinformatics/RESULTS.md
Catalytic His119 maps to target His134; all seven annotated nucleotide-binding positions are preserved.
GO:0045022 early endosome to late endosome transport
ISS PMID:24528630 Notch signaling during development requires the function of ...
NEW
Summary: Awd supports progression of endocytosed receptor cargo beyond early endosomes.
Reason: The primary fly study combines mutant clones, live receptor trafficking, compartment markers and Rab5/NICD epistasis to place Awd in early-endosomal maturation required for receptor progression. The exact accession retains the complete characterized enzyme sequence with an N-terminal extension, supporting same-gene transfer of this broad role. Direct nucleotide delivery to Rab5 or dynamin is a mechanistic hypothesis, not an established reaction channel.
Taken together, these results suggest that during Notch signaling awd function is downstream of or is required for Rab5 function in promoting maturation of early endosomes.
file:DROME/awd/awd-bioinformatics/RESULTS.md
Catalytic His119 maps to target His134; all seven annotated nucleotide-binding positions are preserved.
Core Functions
Maintains nucleotide-triphosphate pools through reversible phosphate transfer using a phosphohistidine intermediate.
We purified the nucleoside diphosphate kinases from wild-type and mutant larvae by a simple procedure involving affinity chromatography on blue Sepharose.
file:DROME/awd/awd-reference-P08879-uniprot.txt
The ATP gamma phosphate is transferred to the NDP beta CC phosphate via a ping-pong mechanism, using a phosphorylated active-site CC intermediate.
file:DROME/awd/awd-bioinformatics/RESULTS.md
Catalytic His119 maps to target His134; all seven annotated nucleotide-binding positions are preserved.
Taken together, these results suggest that during Notch signaling awd function is downstream of or is required for Rab5 function in promoting maturation of early endosomes.
These computational predictions are reviewed separately from the GOA annotation set used for this review. The assessments below are from this project and do not constitute official GO annotations or endorsement by GO/UniProt. They are not included in the existing annotation review above.
The ProtNLM2 API snapshot retrieved 2026-09-08 contains no GO-term predictions for A0A0B4LHX6. Nucleoside diphosphate kinase activity (GO:0004550) is a strongly supported omission candidate: purified Drosophila awd protein has the activity, and the selected 168-residue product contains the entire characterized 153-residue enzyme sequence, including its catalytic histidine and nucleotide-binding positions. The disagreement between FlyBase and reviewed UniProt about N-terminal initiation does not alter that conserved catalytic core; the historical prediction-time sequence is not established by the current comparison. The separate FUNCTION paragraph describing NDP-kinase phosphate transfer is CNN. This completed record assesses the absence of GO output; predictions is empty because no GO or EC prediction was emitted. The narrative judgment remains in the linked function review and is not a score assigned to the omission.