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RESEARCH SUMMARY:
The long term goal of our research is to
elucidate the mechanisms of secretory protein transport through
the organelle called the Golgi complex. This organelle is
a stack of disk-shaped membranes that serves as the central
processing and sorting center for newly synthesized secretory
proteins. Although this organelle has been intensively studied
for more than 100 years, it's still not known how secretory
proteins move through the Golgi stack. Elucidating this mechanism
has taken on an new sense of urgency, since links between
human pathological disorders and defects in Golgi transport,
processing, and sorting functions are emerging at an accelerating
pace.
Our experimental approach has been to reconstitute intra-Golgi
transport in vitro. When our studies began, it was thought
that transport vesicles move secretory proteins between the
disks or cisternae of the Golgi stack. What we found, however,
is that secretory proteins stay in the cisternae of the Golgi
stack, while the Golgi processing enzymes move between these
cisternae in small transport vesicles. These results most
closely fit the currently popular hypothesis that transport
through the Golgi complex occurs by "cisternal maturation".
Our unique contribution is the finding that these intra-Golgi
transport vesicles are distinct from all currently known vesicle
types. Thus, our current goal of isolating and characterizing
these novel vesicles has significant ground-breaking potential.
With our well characterized systems for generating and detecting
functional transport vesicles, and a developing system for
rapidly purifying these vesicles in a functional state, we
are uniquely positioned to achieve this goal.
Nova Red stain of the Golgi complex in cells
expressing an HRP-Golgi enzyme fusion protein
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