Focused fly function hypothesis

Hypothesis: The Drosophila melanogaster protein Q9VVS1 mediates uptake of thiamine pyrophosphate into mitochondria.

Target: Drosophila melanogaster (NCBITaxon:7227), UniProt Q9VVS1. Gene label: Dic4. Verify identity and isoform independently; the gene label is not evidence for the hypothesis.

Original prediction

Mitochondrial transporter that mediates uptake of thiamine pyrophosphate (ThPP) into mitochondria

Decisive question

Determine whether the exact protein supports thiamine-pyrophosphate transport. Establish its placement among experimentally characterized mitochondrial carriers and compare substrate-recognition residues and transport mechanisms, including competing substrate assignments. Read the substrate panel and controls of any direct Dic4 reconstitution study; failure to transport a tested substrate does not exclude an untested one. Separate mitochondrial localization, transport competence, substrate specificity and uptake direction. Identify what structural/evolutionary evidence can resolve and what still needs transport measurements.

Identity and sequence

• Target record: https://www.uniprot.org/uniprotkb/Q9VVS1/entry
• FlyBase identifier(s) from the cohort identity mapping: FBgn0036808.
• Frozen current UniProt sequence: 302 residues; SHA-256 2f5383151315d764c10b9751f7af5754f60eb89416ded2ec518ea01bb71f6b5c.
• The sequence was frozen for the fly cohort on 2026-09-08. It is not established as the original prediction-time input. Analyze this sequence explicitly and document any alternate accession, version or isoform you analyze.

>Q9VVS1 Drosophila melanogaster Dic4
MPVFDDHFLGDCHDEPEGLLPRWWFGGFASMCVAFAVAPIDIVKTHMQIQRQKRSILGTV
KRIHSLKGYLGFYDGFSAAILRQMTSTNIHFIVYDTGKKMEYVDRDSYLGKIILGCVAGA
CGSAFGIPTDLINVRMQTDMKEPPYKRRNYKHVFDGLIRIPKEEGWKALYKGGSVAVFKS
SLSTCSQIAFYDIIKTEVRKNISVNDGLPLHFLTSLGTSIISSAITHPLDVVRTIMMNSR
PGEFRTVFQASVHMMRFGVMGPYRGFVPTIVRKAPATTLLFVLYEQLRLHFGICSLGGEK
YN

Primary literature lead to inspect (not a preassigned conclusion): https://pubmed.ncbi.nlm.nih.gov/21130726/

Evidence and deliverable

Use primary literature and public sequence, structural and genomic resources. This is a focused mechanistic investigation, not a general gene overview. Seek supporting, contrary and competing explanations; an unresolved result is acceptable. Distinguish direct fly experiments, justified transfers and results on a different isoform. Do not equate missing target experiments with evidence of absence.

Do not consult the ai-gene-review repository's current reviews, generated research summaries or local bioinformatics analyses; these are held out for comparison. Agreement with ARBA or repeated prediction text does not validate the biology. Save executed methods/code, actual analysis outputs, sequence identifiers and primary-source URLs/DOIs/PMIDs. Report decisive evidence and limitations, not just a verdict. Do not fabricate computations or use docking/structural resemblance alone as experimental validation.