Evidence map›Paper›PMID 9083693›Full record

ArticleBiophysical journal1997

Photobleaching recovery and anisotropy decay of green fluorescent protein GFP-S65T in solution and cells: cytoplasmic viscosity probed by green fluorescent protein translational and rotational diffusion.

R Swaminathan, C P Hoang, A S Verkman

Open access · bronzeAbstract read
In one paragraph

Article in Biophysical journal, 1997. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 231 papers.

0numbers the graph read from it
0cells of the map it votes in
231citing papers in PubMed
33.5field-weighted citation impact, top 1% of its field
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

231 citing papers in PubMed, 628 citations in OpenAlex.

  1. Article
  2. Article
  3. Electrostatic interactions constrain generalization of porous-media models for intracellular diffusion in mammalian cells.Proceedings of the National Academy of Sciences of the United States of America · 2026
    Article
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  6. Cytoplasmic crowding acts as a porous medium reducing macromolecule diffusion.Proceedings of the National Academy of Sciences of the United States of America · 2026
    Article
  7. Review
  8. Article
  9. Article
  10. Article
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  12. Enzymatic Reactions Dictated by the 2D Membrane Environment.The journal of physical chemistry letters · 2025
    Article
  13. Article
  14. Review
  15. Article
  16. Article
  17. Article
  18. Article
  19. Translation Dynamics of Single mRNAs in Live Cells.Annual review of biophysics · 2024
    Review
  20. Article

171 more citing papers are in PubMed but not listed here.

4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

3 authors at 1 institution in 1 country.

R SwaminathanDepartment of Medicine, University of California, San Francisco 94143, USA.
C P Hoang
A S Verkman
University of California, San Francisco · US

Funding

APPLICATION OF NOVEL OPTICAL METHODS TO CELL DYNAMICSR01DK043840 · NIDDK · UNIVERSITY OF CALIFORNIA SAN FRANCISCO · PI VERKMAN, ALAN S · 1993 to 2001
$494k
ROLE OF THE MEMBRANE SKELETON IN PATHOLOGIC RED CELLSR01DK016095 · NIDDK · UNIVERSITY OF CALIFORNIA SAN FRANCISCO · PI SHOHET, STEPHEN B · 1986 to 2000
$230k
SINGLE CHANNEL KINETICS OF WILD-TYPE AND MUTANT CFTRP50HL042368 · NHLBI · UNIVERSITY OF CALIFORNIA SAN FRANCISCO · PI FINKBEINER, WALTER E · 1988 to 1997
–
NHLBI NIH HHS HL42368NIDDK NIH HHS DK16095NIDDK NIH HHS DK43840
6 · The paper itself

Abstract

The green fluorescent protein (GFP) was used as a noninvasive probe to quantify the rheological properties of cell cytoplasm. GFP mutant S65T was purified from recombinant bacteria for solution studies, and expressed in CHO cell cytoplasm. GFP-S65T was brightly fluorescent in solution (lambda ex 492 nm, lambda em 509 nm) with a lifetime of 2.9 ns and a rotational correlation time (tc) of 20 ns. Recovery of GFP fluorescence after photobleaching was complete with a half-time (t1/2) in aqueous saline of 30 +/- 2 ms (5-micron diameter spot), giving a diffusion coefficient of 8.7 x 10(-7) cm2/s. The t1/2 was proportional to solution viscosity and was dependent on spot diameter. In contrast to fluorescein. GFP photobleaching efficiency was not affected by solution O2 content, triplet state quenchers, singlet oxygen scavengers, and general radical quenchers. In solutions of higher viscosity, an additional, rapid GFP recovery process was detected and ascribed to reversible photobleaching. The t1/2 for reversible photobleaching was 1.5-5.5 ms (relative viscosity 5-250), was independent of spot diameter, and was unaffected by O2 or quenchers. In cell cytoplasm, time-resolved microfluorimetry indicated a GFP lifetime of 2.6 ns and a tc of 36 +/- 3 ns, giving a relative viscosity (cytoplasm versus water) of 1.5. Photobleaching recovery of GFP in cytoplasm was 82 +/- 2% complete with a t1/2 of 83 +/- 6 ms, giving a relative viscosity of 3.2. GFP translational diffusion increased 4.7-fold as cells swelled from a relative volume of 0.5 to 2. Taken together with measurements of GFP translation and rotation in aqueous dextran solutions, the data in cytoplasm support the view that the primary barrier to GFP diffusion is collisional interactions between GFP and macromolecular solutes.

Indexed as

AnimalsCytoplasmDiffusionEscherichia coliFluoresceinFluoresceinsFluorescence PolarizationGreen Fluorescent ProteinsKineticsLuminescent ProteinsMutagenesis, Site-DirectedRecombinant Fusion ProteinsScyphozoaSpectrometry, FluorescenceTransfectionViscosityFluoresceinFluoresceinsGreen Fluorescent ProteinsLuminescent ProteinsRecombinant Fusion Proteins

Identifiers

PMID9083693
PMCPMC1184383
OpenAlexW1993645665

What OpenQuestion holds

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Read underepoch 390

Registered trials

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.