Affinage

DRAM2

DNA damage-regulated autophagy modulator protein 2 · UniProt Q6UX65

Length
266 aa
Mass
29.8 kDa
Annotated
2026-06-09
21 papers in source corpus 9 papers cited in narrative 10 extracted findings
Cross-family judge vs UniProt: Affinage preferred faithfulness: 6/6 claims corpus-supported (100%)

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

DRAM2 is a transmembrane lysosomal protein that functions as a positive regulator of autophagy and a modulator of cell fate (PMID:19895784, PMID:21584698). It promotes autophagosome formation by physically engaging the core autophagy machinery: DRAM2 binds BECN1 and UVRAG, displacing the inhibitor RUBCN from the BECN1 complex and thereby enhancing PI3K activity, which drives autophagosome formation and phagosomal maturation in macrophages confronting Mycobacterium tuberculosis (PMID:27764573). DRAM2 abundance is set transcriptionally and post-transcriptionally—it is repressed by MIR144*/hsa-miR-144-5p acting on its 3'-UTR and induced via AMPK during autophagy activation (PMID:27764573). Its subcellular destination is governed by RPS6KA3/RSK2-mediated phosphorylation at Ser263 in the cytosolic tail, which licenses AP3D1/AP-3 adaptor binding and AP-3-dependent trafficking to the late endosomal-lysosomal pathway to support autolysosome formation; the non-phosphorylatable S263A mutant fails to bind AP-3, mistraffics toward plasma membrane-proximal compartments, and shifts DRAM2 output toward exosome secretion rather than autophagy (PMID:42059423). Beyond autophagy, DRAM2 influences proliferation and migration in cancer cells, including a mutual repression with p53 and promotion of gemcitabine resistance through enhanced autophagy (PMID:30755245, PMID:32864010). Loss-of-function mutations in DRAM2 cause an inherited retinal dystrophy (CORD21), consistent with its localization to photoreceptor inner segments and the apical RPE surface and with autophagic, lysosomal, and lipid-metabolism defects in patient-derived retinal cells (PMID:25983245, PMID:38964324).

Mechanistic history

Synthesis pass · year-by-year structured walk · 9 steps
  1. 2009 Medium

    Established DRAM2 as a lysosomal DRAM-homolog with a regulatory role in cell death, opening the question of its cellular function.

    Evidence Subcellular fractionation/immunofluorescence plus co-expression and siRNA knockdown with cell death readout

    PMID:19895784

    Open questions at the time
    • Did not define the molecular pathway linking DRAM2 to death
    • No direct binding partners identified
  2. 2011 Medium

    Showed DRAM2 is a positive regulator of autophagy induction, reframing the lysosomal protein as part of the autophagy machinery.

    Evidence GFP-LC3 puncta assay and LC3-II immunoblotting with siRNA knockdown under starvation

    PMID:21584698

    Open questions at the time
    • Mechanism of autophagy promotion not defined
    • No molecular partners identified
  3. 2015 Medium

    Connected DRAM2 loss-of-function to human inherited retinal dystrophy and tissue-specific expression, establishing physiological relevance in photoreceptor/RPE biology.

    Evidence Immunohistochemistry on retinal tissue plus homozygosity mapping and exome sequencing of patients

    PMID:25983245

    Open questions at the time
    • Mechanism linking DRAM2 loss to photoreceptor degeneration not established
    • Functional inference from expression pattern only
  4. 2016 High

    Defined the molecular mechanism of DRAM2-driven autophagy—binding BECN1/UVRAG to displace RUBCN and enhance PI3K activity—and identified MIR144*/AMPK as upstream regulators of DRAM2 levels.

    Evidence Reciprocal Co-IP, PI3K activity assay, autophagosome assays, and 3'-UTR luciferase reporter in primary human macrophages/monocytes

    PMID:27764573

    Open questions at the time
    • Structural basis of RUBCN displacement not resolved
    • Whether this complex operates outside macrophage/Mtb context not tested here
  5. 2019 Medium

    Extended DRAM2 function to cancer cell proliferation and migration via RHO-GTPase and cell-cycle regulators and a mutual repression with p53.

    Evidence Western blotting, Transwell migration, cell cycle analysis, and bidirectional p53/DRAM2 epistasis in NSCLC cells

    PMID:30755245

    Open questions at the time
    • Direct vs indirect basis of DRAM2-p53 repression unclear
    • Mechanistic link to autophagy activity not established
  6. 2020 Medium

    Linked DRAM2-driven autophagy to chemoresistance, showing DRAM2 can promote cell survival under cytotoxic stress.

    Evidence siRNA/overexpression with colony formation, apoptosis flow cytometry, and EM for autophagy in gemcitabine-resistant bladder cancer cells

    PMID:32864010

    Open questions at the time
    • Upstream signal driving DRAM2 upregulation in resistance unknown
    • Molecular partners in this context not examined
  7. 2024 Medium

    Used patient-derived retinal models to show DRAM2 mutation impairs autophagic flux, lysosomal function, and lipid metabolism and pointed to vesicular trafficking partners.

    Evidence iPSC-derived retinal organoids/RPE from CORD21 patients with autophagic flux, lysosomal enzyme, lipid, and IP-MS interactome assays

    PMID:38964324

    Open questions at the time
    • IP-MS trafficking partners not individually validated
    • Causal chain from trafficking defect to degeneration not resolved
  8. 2024 Medium

    Demonstrated that Dram2 knockout alone does not cause retinal degeneration in mice, indicating loss of DRAM2 is insufficient for dystrophy in this model.

    Evidence CRISPR/Cas9 Dram2 knockout mice with ERG, opsin/rhodopsin immunostaining, TUNEL, and gliosis assays

    PMID:39520804

    Open questions at the time
    • Species differences or compensatory mechanisms not identified
    • Whether stress/age challenge reveals a phenotype not tested
  9. 2026 High

    Resolved how DRAM2's destination and function are switched—RSK2 phosphorylation at Ser263 enables AP-3-dependent lysosomal trafficking for autophagy, while its loss redirects DRAM2 to plasma membrane compartments and exosome secretion.

    Evidence Co-IP, in-cell kinase assay with phospho-Ser263 validation, S263A mutagenesis, nanoparticle tracking, and in vivo xenograft

    PMID:42059423

    Open questions at the time
    • Upstream MAPK/RSK2 activating signals in physiological contexts not mapped
    • Functional cargo and role of DRAM2-driven exosomes not characterized

Open questions

Synthesis pass · forward-looking unresolved questions
  • How DRAM2's distinct functions—autophagy promotion, cell-death/cancer modulation, retinal maintenance, and exosome secretion—are integrated and tissue-specifically deployed remains unresolved.
  • No structural model of DRAM2 in the BECN1/UVRAG complex
  • Mechanism reconciling the mouse KO negative phenotype with human disease unknown
  • Physiological triggers selecting lysosomal vs exosomal routing undefined

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0060090 molecular adaptor activity 2 GO:0098772 molecular function regulator activity 1
Localization
GO:0005764 lysosome 3 GO:0005768 endosome 1 GO:0005886 plasma membrane 1
Pathway
R-HSA-9612973 Autophagy 3 R-HSA-168256 Immune System 2 R-HSA-5653656 Vesicle-mediated transport 2
Partners
AP3D1BECN1RPS6KA3RUBCNUVRAG

Evidence

Reading pass · 10 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2009 DRAM2 is a novel DRAM-homologous transmembrane protein that localizes primarily to the lysosome and co-localizes with DRAM. Co-expression of DRAM2 with DRAM significantly induced cell death, whereas silencing of endogenous DRAM2 attenuated cell death, establishing DRAM2 as a cell death regulator. Subcellular fractionation/immunofluorescence for localization; co-expression and siRNA knockdown with cell death readout Biochemical and biophysical research communications Medium 19895784
2011 Overexpression of DRAM2 induces cytoplasmic GFP-LC3 puncta and increases endogenous LC3-II levels, indicating autophagosome formation. Silencing of endogenous DRAM2 interferes with starvation-induced autophagy, establishing DRAM2 as a positive regulator of autophagy induction. GFP-LC3 puncta assay, LC3-II immunoblotting, siRNA knockdown under starvation conditions Molecular biology reports Medium 21584698
2015 DRAM2 encodes a transmembrane lysosomal protein; immunohistochemical analysis showed DRAM2 localization to photoreceptor inner segments and the apical surface of retinal pigment epithelial (RPE) cells, suggesting involvement in photoreceptor renewal and recycling. Immunohistochemistry on retinal tissue sections; genetic mapping (homozygosity mapping + exome sequencing) identifying loss-of-function mutations causing retinal dystrophy American journal of human genetics Medium 25983245
2016 DRAM2 physically interacts with BECN1 and UVRAG (core autophagy machinery components), leading to displacement of RUBCN from the BECN1 complex and enhancement of PI3K activity, thereby promoting autophagosome formation and phagosomal maturation in macrophages challenged with Mycobacterium tuberculosis. Co-immunoprecipitation (DRAM2-BECN1, DRAM2-UVRAG interactions); PI3K activity assay; autophagosome formation assay; overexpression and inhibition of MIR144* with DRAM2 readout Autophagy High 27764573
2016 MIR144*/hsa-miR-144-5p directly targets the 3'-UTR of DRAM2 mRNA, downregulating DRAM2 protein expression and decreasing autophagosome formation in human monocytes. Mtb infection induces MIR144* expression which suppresses DRAM2, while autophagy activators upregulate DRAM2 via AMPK activation. 3'-UTR luciferase reporter assay; overexpression/inhibition of miR-144* with qPCR and western blot for DRAM2; AMPK inhibitor experiments Autophagy High 27764573
2019 DRAM2 overexpression in NSCLC cells increases expression of RHO-family GTPases (RAC1, RHOA, RHOC, ROCK1) and decreases RHOB, promoting cell migration; it also increases CDK4 and CyclinD3 while decreasing p27, promoting cell cycle progression. DRAM2 expression is negatively correlated with p53; knockdown of DRAM2 increases p53 and p21, and overexpression of p53 decreases DRAM2, establishing a mutual repression between DRAM2 and p53. Western blotting for pathway proteins; Transwell migration assay; cell cycle analysis; overexpression and siRNA knockdown; p53 overexpression rescue experiment Journal of experimental & clinical cancer research Medium 30755245
2020 DRAM2 upregulation in gemcitabine-resistant bladder cancer cells promotes autophagy and chemoresistance. Silencing DRAM2 in resistant T24-GEM cells inhibited gemcitabine-induced autophagy and restored drug sensitivity; conversely, DRAM2 overexpression in parental T24 cells enhanced autophagy and decreased apoptosis under gemcitabine treatment. siRNA knockdown and overexpression; colony formation assay; flow cytometry apoptosis assay; electron microscopy for autophagy Archives of medical science Medium 32864010
2024 iPSC-derived retinal organoids and RPE cells from CORD21 (DRAM2-mutant) patients exhibit defects in autophagic flux, accumulation of aberrant lysosomal content, reduced lysosomal enzyme activity, and abnormalities in lipid metabolism. Proteomic analysis identified potential interactions of DRAM2 with vesicular trafficking proteins, suggesting DRAM2 involvement in vesicular trafficking. iPSC-derived retinal organoids and RPE cells from CORD21 patients; autophagic flux assays; lysosomal enzyme activity assays; lipid metabolism analysis; immunoprecipitation-mass spectrometry for interactome Stem cell reports Medium 38964324
2024 Dram2 knockout mice generated by CRISPR/Cas9 do not exhibit retinal degeneration, loss of cone cells, defects in photoresponse, or changes in rhodopsin localization, gliosis, or apoptosis under normal conditions, indicating that Dram2 loss alone is insufficient to cause retinal dystrophy in mice. CRISPR/Cas9 Dram2 knockout mice; ERG (electroretinography); immunostaining for cone opsins, rhodopsin, and disc proteins; TUNEL apoptosis assay; GFAP gliosis assay Vision research Medium 39520804
2026 RPS6KA3/RSK2 kinase (downstream of MAPK) directly interacts with DRAM2 and phosphorylates it at Ser263 within its cytosolic tail. This phosphorylation is required for AP3D1/AP-3 adaptor complex binding and AP-3-dependent trafficking of DRAM2 to the late endosomal-lysosomal pathway, enabling autolysosome formation and autophagic flux. The non-phosphorylatable DRAM2-S263A mutant fails to bind AP3D1/AP-3, exhibits defective lysosomal trafficking, and is redistributed toward plasma membrane-proximal compartments where it enhances exosome secretion instead. Co-immunoprecipitation (RSK2-DRAM2, DRAM2-AP3D1); in vitro/in-cell kinase assay with phospho-Ser263 validation; site-directed mutagenesis (S263A); nanoparticle tracking analysis for exosomes; in vivo tumor xenograft with DRAM2-S263A; autophagic flux assays Autophagy High 42059423

Source papers

Stage 0 corpus · 21 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2016 MIR144* inhibits antimicrobial responses against Mycobacterium tuberculosis in human monocytes and macrophages by targeting the autophagy protein DRAM2. Autophagy 108 27764573
2020 Dexmedetomidine inhibits inflammatory response and autophagy through the circLrp1b/miR-27a-3p/Dram2 pathway in a rat model of traumatic brain injury. Aging 58 33147167
2016 MicroRNA-125b promotes tumor growth and suppresses apoptosis by targeting DRAM2 in retinoblastoma. Eye (London, England) 55 27518550
2011 The expression of damage-regulated autophagy modulator 2 (DRAM2) contributes to autophagy induction. Molecular biology reports 53 21584698
2015 Biallelic mutations in the autophagy regulator DRAM2 cause retinal dystrophy with early macular involvement. American journal of human genetics 41 25983245
2020 Silencing miR-125b-5p attenuates inflammatory response and apoptosis inhibition in mycobacterium tuberculosis-infected human macrophages by targeting DNA damage-regulated autophagy modulator 2 (DRAM2). Cell cycle (Georgetown, Tex.) 38 33121314
2009 Reduced expression of DRAM2/TMEM77 in tumor cells interferes with cell death. Biochemical and biophysical research communications 33 19895784
2019 DRAM2 acts as an oncogene in non-small cell lung cancer and suppresses the expression of p53. Journal of experimental & clinical cancer research : CR 25 30755245
2015 Disease Expression in Autosomal Recessive Retinal Dystrophy Associated With Mutations in the DRAM2 Gene. Investigative ophthalmology & visual science 14 26720460
2020 KCNQ1OT1 accelerates gastric cancer progression via miR-4319/DRAM2 axis. International journal of immunopathology and pharmacology 9 33100093
2019 Characterization of the cone-rod dystrophy retinal phenotype caused by novel homozygous DRAM2 mutations. Experimental eye research 8 31394102
2022 The Clinical Spectrum and Disease Course of DRAM2 Retinopathy. International journal of molecular sciences 6 35806404
2020 Clinical Course and Electron Microscopic Findings in Lymphocytes of Patients with DRAM2-Associated Retinopathy. International journal of molecular sciences 6 32079136
2015 Genetic Variants on Chromosome 1p13.3 Are Associated with Non-ST Elevation Myocardial Infarction and the Expression of DRAM2 in the Finnish Population. PloS one 6 26509668
2020 Up-regulation of DRAM2 promotes tolerance of bladder transitional cell carcinoma to gemcitabine. Archives of medical science : AMS 5 32864010
2025 DRAM2 inhibits white spot syndrome virus infection via activating autophagy in Penaeus vannamei. Fish & shellfish immunology 4 40020951
2024 Retinal cells derived from patients with DRAM2-dependent CORD21 dystrophy exhibit key lysosomal enzyme deficiency and lysosomal content accumulation. Stem cell reports 3 38964324
2025 Integrating transcriptomics and scPagwas analysis predicts naïve CD4 T cell-related gene DRAM2 as a potential biomarker and therapeutic target for colorectal cancer. BMC cancer 2 39984869
2025 Combination Therapy of Estrogen and Progesterone Attenuates Behavioral Impairments and Autophagy via circLrp1b/miR-27a-3p/Dram2 Pathway After Traumatic Brain Injury. Molecular neurobiology 2 40442535
2024 Lack of retinal degeneration in a Dram2 knockout mouse model. Vision research 2 39520804
2026 RPS6KA3/RSK2-mediated phosphorylation of DRAM2 promotes lysosomal targeting and autophagic flux in melanoma. Autophagy 0 42059423

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