MEMBRANE FUSION &THE ENDOCYTIC PATHWAY

Project: Research project

Project Details

Description

The long term goal of the proposed research is an understanding
of the molecular mechanisms of membrane fusion and targeting in
eukaryotic cells and viruses. The major approach is to analyze
the fusion reaction of Semliki Forest Virus (SFV), an extremely
well-characterized enveloped virus. This virus infects cells via a
membrane fusion reaction triggered by the acid pH present in
endocytic vesicles. Such a pathway mediates infection by
numerous virus families, including those containing such
important pathogens as rabies, herpes, and HTLV-III. Endocytosis
itself represents a key example of vesicle fusion and targeting,
central to the uptake of hormones, nutrients, and growth factors,
and the regulation of cell surface receptors.

The conformational changes in the fusogenic SFV protein will be
analyzed extensively using cloned spike protein genes for wild
type virus, and SFV mutants and revertants which have altered pH
thresholds. Expression studies, sequence analysis, and genetically
engineered chimeras of mutant and wild type spikes will be used
to define the role of the individual spike subunits in fusion.

SFV fusion is strikingly dependent on the presence of cholesterol
in the target membrane. Sterol-depleted cell cultured systems
will be used to define the role of sterol in virus infection.
Interactions of sterol with the virus spike will be analyzed both
biochemically and by generating viral mutants with altered sterol
requirements.

The fusion activity of SFV will also be used as a tool to follow the
origin and movement of endocytic vesicles, using specific
depletion or modification of membrane sterol to mark plasma
membranes.
StatusFinished
Effective start/end date7/1/876/30/88

Funding

  • National Institute of General Medical Sciences

ASJC

  • Biophysics
  • Biochemistry
  • Virology
  • Cell Biology
  • Microbiology

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