Donald E. Fosket
Ph.D., University of Idaho, 1965
Regulation of cytoskeleton formation and function
Email address: defosket@uci.edu
The cytoskeleton is a network of proteinaceous fibers, principally
microtubules and microfilaments, connected to the plasma membrane and
cytoplasmic organelles. As the term cytoskeleton suggests, it is the
major determinant of intracellular cyto-architecture. Additionally,
cytoskeletal elements are important for intracellular transport;
microtubules are the principal components of the mitotic spindle. My
research has focused on the cytoskeletal proteins that comprise
microtubules. We have isolated and characterized tubulin, the principal
protein component of microtubules, from plants. Tubulin can self-assemble
to form microtubules in vitro, yet microtubule formation in cells is
highly regulated, both in terms of the position and time in which
microtubules are formed. How are microtubules formed at a particular time
and place within a given cell? We are attempting to answer this using a
combination of molecular and biochemical techniques. To identify the
unique features of the tubulin protein that are important for its
regulated assembly into microtubules, we have modified tubulin genes so
that the amino acid sequence specified in a particular region of the
tubulin protein is altered. These modified genes then are placed back
into cells where their expression results in the synthesis of a variant
tubulin protein. From the behavior of the variant tubulin protein we are
able to draw conclusions about the importance of different regions of the
protein for its biological function.
Selected Publications
Fosket, D. E. and L. C. Morejohn. 1992. Structural and functional
organization of tubulin. Ann. Rev. Plant Physiol. Plant Mol. Biol.
43:201.
Tonoike, H., I.-N Han, I. Jongewaard, M. Doyle, M. Guiltinan and D.E.
Fosket. 1994. Hypocotyl expression and light down regulation of the
soybean *-tubulin gene, tubB1. The Plant J. 5:343.
Jongewaard, I. A. Colon and D.E. Fosket. 1994. Distribution of
transcripts of the tubB1 *-tubulin gene in developing soybean (Glycine
max [L.] Merr.) seedlings. Protoplasma 183:77.