Biology Reference
In-Depth Information
LD-associated proteins occurred in the center of the cross-fractured lipid ester core
(
Robenek, Robenek, & Troyer, 2005
), but it is not known how those proteins exist in
the hydrophobic environment in a thermodynamically stable way.
13.6
FUTURE DIRECTIONS
There are many remaining questions concerning LDs. One of the questions that mi-
croscopy is expected to address is whether and how LD contacts, continues, or is
contained in membranes of other organelles. This is related to the question of where
and how new LDs are generated. It is postulated that nascent LDs form by deposition
of lipid esters between two membrane leaflets, followed by separation of the lipid
ester globule from the mother membrane, but this hypothetical process has never
been confirmed by microscopy. Nascent LDs are predicted to be very small, but they
are within the spatial resolution of conventional EM. Development of a method that
preserves the structure
in situ
and makes it visible by EM is highly anticipated.
Acknowledgments
We thank Dr Rob Mesman, Dr Matthia Karreman, and Ms. Elly van Donselaar (Utrecht Uni-
versity) for many invaluable inputs on cryosectioning techniques and sharing unpublished
results. We also thank Dr Robert Parton (University of Queensland) for information on the
post-embedding method. The work of our laboratory cited in the chapter was supported by
Grants-in-Aid for Scientific Research and the Global COE Program “Integrated Molecular
Medicine for Neuronal and Neoplastic Disorders” of the Ministry of Education, Culture,
Sports, Science, and Technology of the Japanese Government and The Naito Foundation
Subsidy for Promotion of Specific Research Projects.
References
