ASCB 2013 PressBook - page 3

T H E A M E R I C A N S O C I E T Y F O R C E L L B I O L O G Y
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News from
The American Society
for Cell Biology
53rd Annual Meeting
New Orleans, LA
December 14–18, 2013
Where does the Golgi go?
EMBARGOED
FOR RELEASE
10:00 am, U.S. Central Time
Sunday, December 15, 2013
Contact
Jennifer Lippincott-Schwartz
National Institutes of Health
Building 18T Room 101

18 Library Drive
Bethesda, MD 20892
(301) 402-1010
Author Presents
Sunday, December 15
12:00 PM–1:30 PM
Establishing and Maintaining
Organelle Structure
Presentation 822
Poster B1401
Exhibit Halls B–D
Tuesday, December 17
12:00 PM–1:30 PM
Mitosis and Meiosis
ePoster Talk
Presentation 156
Room 232
High-resolution imaging of Golgi
protein trafficking through the ER
during mitosis
Dylan T. Burnette, Prabuddha
Sengupta, Jennifer Lippincott-
Schwartz
Cell Biology and Metabolism
Program, Eunice Kennedy
Shriver National Institute of Child
Health and Human Development,
National Institutes of Health,
Bethesda, Maryland
High-resolution 3-D imaging
draws sharper picture of Golgi’s
whereabouts when mother cell
packs up for mitosis
C
ell division is the great domestic dra-
ma of a cell’s life. In sickness and in
health, cell division by mitosis is the
complicated yet critical process by which a
mother cell divides into two daughter cells.
But first the mother cell has to pack up her
cellular household contents, disassembling
and dividing up everything for her soon-
to-be-formed daughters. How cells manage
division has been exhaustively studied for
well over a century and yet basic myster-
ies remain. We know that some organelles
such as the endoplasmic reticulum (ER) are
pulled apart before division but keep their
tubular membrane structure intact. Others
like the Golgi, the organelle that sorts out
proteins for delivery inside or outside the
cell, go to pieces after the prophase of mito-
sis through what’s called a “choreographed
disassembly process.”
But where does the Golgi go once it is
in pieces? Until now, microscopes and other
imaging systems could only look so closely
before the disassembled Golgi parts blurred
into ultra-tiny “puncta” and an unresolvable
haze. Now thanks to new 3-D super-resolu-
tion imaging methods, Dylan Burnette and
Prabuddha Sengupta in Jennifer Lippincott-
Schwartz’s lab at the Eunice Shriver National
Institute of Child Health and Human Devel-
opment (NICHD) at NIH in Bethesda, MD,
have a clearer picture and a clear answer.
The researchers started with two plau-
sible theories: In the ER-linked hypothesis,
the Golgi puncta and enzyme haze are
closely held by the ER; in the non-ER-linked
model, the puncta and haze float about on
their own, waiting for cytokinesis when the
two daughter cells separate and the Golgi
body reappears as stacks of membrane-
bound “cisternae,” ready to sort proteins
from the reassembled ER. Powered by their
new imaging technologies, which gave them
far greater resolution than was ever possible
before, the researchers saw clear support
of the ER-linked model—the enzyme haze
sticking close to ER markers with the puncta
clustering near ER exits.
For a second line of proof, the NICHD
researchers followed up with a pharmaco-
logical-based trapping assay that showed
Golgi enzymes being held tightly by the ER
during mitosis. Which means, say the re-
searchers, that Golgi enzymes redistribute
into the ER during mitosis and that they
must follow an ER export pathway to reform
the Golgi at the end of mitosis. Their work
not only resolves a basic cellular question
but shows what new solutions await as these
new technologies give us keener vision and
sharper tools.
Live-cell imaging of the Golgi (green) and DNA (red) throughout the different stages of mitosis (defined by chromosomal
morphology). The montage begins at the end of interphase (G2) in the upper left panel and proceeds in time left to right.
During interphase, the Golgi has a stereotypical localization next to the nucleus (G2, 0min). At the onset of mitosis chro-
mosomes start to condense and the Golgi starts to dramatically redistribute (Prophase, 10min). The Golgi continues this
redistribution into small puncta and a haze distributed throughout the cell through metaphase when the chromosomes
are aligned at the metaphase plate (Metaphase, 40min). As the cell divides, each new daughter cell gets a share of the
Golgi puncta and Golgi haze (Anaphase, 50min). After division both Golgi populations combine to recreate a new Golgi in
each daughter cell (Telophase, 60min).
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