Concept
Protein trafficking
7 studies
Protein trafficking is the directed movement of proteins through cellular compartments to their functional destinations.
Where proteins go determines function — trafficking errors underlie many disease mechanisms taught in biology.
Studies
7
Findings
5
7 supporting · 0 challenging · 0 qualifying citations
Open tensions
1
Currently
What we know
- Multiple empirical papers in this library examine protein trafficking with mechanistic biological findings.
- PDLP1 family proteins target plasmodesmata; PDLP1a has cytoplasmic C-tail and apoplastic DUF26 domains; combined KOs increase GFP movement.
- LYQD mutants altered S2 glycosylation mobility; palmitoylation at cysteine clusters I/II was required for efficient S pp/virus production, Golgi/plasma-membrane targeting, and cell fusion.
- Rab5 is monoubiquitinated at K116, K140, and K165; K140/K165 modifications downregulate the Rab5 endocytic pathway via disrupted partners and nucleotide conversion, while K116 has little localization effect.
- MC4R homodimerizes and undergoes β-arrestin-2–driven endocytosis. Many variants impair trafficking even when cAMP looks normal; gain-of-function alleles link to obesity protection.
Largest unresolved question
Systems and scales differ across protein trafficking studies (species, tissues, methods), so mechanisms should not be over-generalised.
Common misconceptions
Protein trafficking findings from one model organism always transfer to humans.
Model systems teach mechanism; transfer to other species is a separate empirical claim.
Related
Claim ledger
What the evidence shows
Drawn from 7 studies in this library. Mix labels say which citation roles are present; they are not a strength score. Supports means evidence for a finding; Challenges means evidence against a stated position; Qualifies marks scope.
Multiple empirical papers in this library examine protein trafficking with mechanistic biological findings.
- How do proteins find plasmodesmata?
- Spike glycosylation and palmitoylation trafficking
- How does monoubiquitin turn down Rab5?
Study Role Design N Population Outcome How do proteins find plasmodesmata? Supports Animal / in-vitroGFP localization and topology/knockout assays of PDLP plasmodesmal proteins Plant cell-biology localization and trafficking assays — no single sample N Arabidopsis and other plants expressing PDLP family proteins Plasmodesmal targeting of PDLPs and effects on cell-to-cell GFP movement Spike glycosylation and palmitoylation trafficking Supports Animal / in-vitroMutagenesis and 2BP inhibition of SARS-CoV-2 spike glycosylation/palmitoylation trafficking Cell-based spike trafficking/fusion assays — no single primary analytic N Cells expressing wild-type or mutant SARS-CoV-2 spike Spike intracellular trafficking, packaging, and ACE2-mediated fusion How does monoubiquitin turn down Rab5? Supports Animal / in-vitroMapped Rab5 monoubiquitination sites and tested chemically monoubiquitinated Rab5 function Cell-biochemistry of Rab5 ubiquitin sites K116/K140/K165 — no single sample N Cultured cells expressing Rab5 variants Site-specific monoubiquitination downregulating Rab5 endocytic signaling PDLP1 family proteins target plasmodesmata; PDLP1a has cytoplasmic C-tail and apoplastic DUF26 domains; combined KOs increase GFP movement.
LYQD mutants altered S2 glycosylation mobility; palmitoylation at cysteine clusters I/II was required for efficient S pp/virus production, Golgi/plasma-membrane targeting, and cell fusion.
Rab5 is monoubiquitinated at K116, K140, and K165; K140/K165 modifications downregulate the Rab5 endocytic pathway via disrupted partners and nucleotide conversion, while K116 has little localization effect.
MC4R homodimerizes and undergoes β-arrestin-2–driven endocytosis. Many variants impair trafficking even when cAMP looks normal; gain-of-function alleles link to obesity protection.
Debates
Tensions and limits
Some items are genuine disagreements on the same question. Others mark different assays, populations, or outcomes.
Systems and scales differ across protein trafficking studies (species, tissues, methods), so mechanisms should not be over-generalised.
Systems and scales differ across protein trafficking studies (species, tissues, methods), so mechanisms should not be over-generalised.
- How do proteins find plasmodesmata?
- Spike glycosylation and palmitoylation trafficking
- How does monoubiquitin turn down Rab5?
Study Role Design N Population Outcome How do proteins find plasmodesmata? Supports Animal / in-vitroGFP localization and topology/knockout assays of PDLP plasmodesmal proteins Plant cell-biology localization and trafficking assays — no single sample N Arabidopsis and other plants expressing PDLP family proteins Plasmodesmal targeting of PDLPs and effects on cell-to-cell GFP movement Spike glycosylation and palmitoylation trafficking Supports Animal / in-vitroMutagenesis and 2BP inhibition of SARS-CoV-2 spike glycosylation/palmitoylation trafficking Cell-based spike trafficking/fusion assays — no single primary analytic N Cells expressing wild-type or mutant SARS-CoV-2 spike Spike intracellular trafficking, packaging, and ACE2-mediated fusion How does monoubiquitin turn down Rab5? Supports Animal / in-vitroMapped Rab5 monoubiquitination sites and tested chemically monoubiquitinated Rab5 function Cell-biochemistry of Rab5 ubiquitin sites K116/K140/K165 — no single sample N Cultured cells expressing Rab5 variants Site-specific monoubiquitination downregulating Rab5 endocytic signaling
PaperFren reads this as a limit on how far one study travels — different assays, populations, or outcomes — not a forced fight between papers.
Timeline
How understanding moved
Study years are when the paper was published. Evidence edits are dated changes to this page's claims. Explanations are when PaperFren added a Discovery — not a claim that the science happened that day.
2026
Concept page published
Protein trafficking
Change log
What changed
Dated edits to this page's evidence: studies added or removed from a claim, claims added or withdrawn, and new explanations tagged here. Coverage edits are distinct from reviewed research changes and corrections. Dates record PaperFren updates; study publication dates appear in the timeline.
- Coverage updated · Concept page published
Papers
7 studies in this library bear on Protein trafficking, ordered by citations.
- Mapping the faces of mitochondria and ER
APEX2 proximity biotinylation yields high-quality proteomic maps of cytosol-facing outer mitochondrial and ER membranes in living human cells.
- How do proteins find plasmodesmata?
PDLP1 is a type I membrane protein targeted to plasmodesmata; altering PDLP dosage changes GFP cell-to-cell trafficking.
- What proteins build the caveolar coat?
Caveolins and cavins purify as a caveolar coat complex with Cavin 1 as a core trimeric component.
- SNARE timing in sperm acrosome exocytosis
Sperm acrosome exocytosis proceeds via ordered SNARE assembly/disassembly around intra-acrosomal Ca2+ release.
- How MC4R variants scramble receptor trafficking
Obesity-linked MC4R mutations disrupt plasma-membrane localization, endocytosis and β-arrestin pathways beyond classical cAMP loss-of-function.
- Spike glycosylation and palmitoylation trafficking
Glycosylation motifs and cysteine palmitoylation steer SARS-CoV-2 spike maturation, Golgi trafficking, and fusion.
- How does monoubiquitin turn down Rab5?
Rab5 is monoubiquitinated at specific lysines; ubiquitin at K140/K165 disrupts effector binding and downregulates endocytic trafficking.
Compare studies
Select 2–10 studies. Design and N are labels, not a ranking.
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Questions
What is still open
Systems and scales differ across protein trafficking studies (species, tissues, methods), so mechanisms should not be over-generalised.
Ask PaperFren about Protein trafficking
Study this conceptflashcards and short-answer questions
What is Protein trafficking?
Protein trafficking is the directed movement of proteins through cellular compartments to their functional destinations.
Why does Protein trafficking matter for biology undergraduates?
Where proteins go determines function — trafficking errors underlie many disease mechanisms taught in biology.