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Associate Professor of Biology
{ Email Professor
Allen }
Teaching Area: Physiology - the study of how molecules,
cells, organs, and organisms function
I teach three courses, each of which seeks to develop students'
mastery of physiological concepts, understanding of the experimental
evidence supporting these concepts, and ability to design
meaningful experiments. Animal Physiology (Biol 312),
which is given in the fall, examines the function of the body
from molecular to oganismal levels and considers topics ranging
from the communication between cells to the adaptations of
animals to pregnancy or to extreme environments. Cell Physiology
(Biol 313), taught in the spring, concerns the vibrant activity
of cells and focuses on the intracellular machinery and signaling
pathways supporting this activity, with examples drawn from
developmental biology, immunology, and cancer biology. Cell
Physiology Research (Biol 314), the third course, seeks
to introduce students to the methods of research, from the
formulation of an experiment to the presentation of findings
and conclusions. Students work in pairs on a problem selected
in consultation with the teacher and gain proficiency in one
or more methods drawn from recombinant DNA technology, genetics,
and cell biology.
Research Interests: Contraction of Muscle and Its
Regulation
Before reading about my research interests, here's an experiment
to do on yourself: hold a tennis ball in your hand and determine
how many times you can squeeze the ball.
If you are like most people, you'll probably manage a total
of about 100 squeezes, much less than the number of contractions
your heart probably will tirelessly make in your lifetime
(on average, about 2,500,000,000 beats!).
Research in my laboratory addresses how skeletal and cardiac
muscles turn force production on and off, as well as how individual
muscles gain unique contractile characteristics, such as the
heart's ability to contract repeatedly for a seemingly indefinite
period of time. At the simplest level, muscle has two components:
a motor capable of transforming chemical energy (ATP) into
mechanical work (force generation and shortening of muscle
cells), and a calcium-sensitive switch for the motor. The
four proteins forming the switch have been known for 25 years;
however, the way they work is largely a mystery. Mutations
in the switch proteins can cause lethal heart disease in humans
and improper muscle development in the nematode Caenorhabditis
elegans and the fly Drosophila melanogaster.
Such knowledge, if it were available, would guide pharmacologists
and physicians in the treatment of muscular diseases, e.g.,
the weakened heart of an elderly patient, for whom stronger,
perhaps more rapid heart beats might be desired.
To clarify how the switch mechanistically work, we are engineering
mutations in genes that code for proteins in the switch, transferring
the mutant genes into C. elegans, and then examining
the consequences of these mutations to muscle function in
C. elegans. By systematically mutating the genes, we
shall be able to map particular functions of the switch (e.g.,
controlling the speed of contraction) to discrete protein
surfaces. Such knowledge will enable drug designers to produce
drugs that most effectively treat various muscular disorders.
1990-96 Postdoctoral Fellow, University of Pennsylvania
1990 Ph.D. (Physiology and Biophysics), University of Washington
1984 B.S.E. (Bioengineering), University of Pennsylvania
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