Animations of the kinesin motor protein have captured something of the astounding orchestration of processes within the cell. We already know quite a lot about the microtubules on which kinesin â€œwalksâ€. Protofilaments made of tubulin assemble to form a sheet which then folds to form the microtubule structure. The join of the two edges of the sheet has not been previously considered very interesting. Andreas Hoenger is quoted as saying: "Until now the function of the seam has been unknown and it has been largely ignored as an odd and irrelevant part of the microtubule lattice. Our experiments now reveal it as a central spot where microtubule stability can be regulated."
New research has identified a protein Mal3p that plays a crucial role in assembly of the microtubules, described as a molecular â€œzipperâ€. Cellular controls on this protein lead to assembly, disassembly and rapid switching. There are indications that the same protein â€œcould also play a more active role in transportationâ€. A remarkable photograph of an opening microtubule is here.
Although the new studies have involved yeast cells, the Mal3p protein is widely found in different organisms, and the results are considered likely to be of general relevance.
Every new advance in understanding the molecular machines within the cell reveals complex specified information and strengthens the case for ID.
The Schizosaccharomyces pombe EB1 Homolog Mal3p Binds and Stabilizes the Microtubule Lattice Seam
Linda Sandblad, Karl Emanuel Busch, Peter Tittmann, Heinz Gross, Damian Brunner, and Andreas Hoenger
Cell, 127(7), 29 December 2006, Pages 1415-1424
Summary: End binding 1 (EB1) proteins are highly conserved regulators of microtubule dynamics. Using electron microscopy (EM) and high-resolution surface shadowing we have studied the microtubule-binding properties of the fission yeast EB1 homolog Mal3p. This allowed for a direct visualization of Mal3p bound on the surface of microtubules. Mal3p particles usually formed a single line on each microtubule along just one of the multiple grooves that are formed by adjacent protofilaments. We provide structural data showing that the alignment of Mal3p molecules coincides with the microtubule lattice seam as well as data suggesting that Mal3p not only binds but also stabilizes this seam. Accordingly, Mal3p stabilizes microtubules through a specific interaction with what is potentially the weakest part of the microtubule in a way not previously demonstrated. Our findings further suggest that microtubules exhibit two distinct reaction platforms on their surface that can independently interact with target structures such as microtubule-associated proteins, motors, kinetochores, or membranes.
Kikkawa, M. and Metlagel, Z. A molecular â€˜zipperâ€™ for microtubules,
Cell, Volume 127, Issue 7, 29 December 2006, Pages 1302-1304.
Roadworks on the motorways of the cell
EurekAlert, 28 December 2006.
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Evolution has become a favorite topic of the news media recently, but for some reason, they never seem to get the story straight. The staff at Discovery Institute's Center for Science and Culture started this Blog to set the record straight and make sure you knew "the rest of the story".
A blogger from New England offers his intelligent reasoning.
We are a group of individuals, coming from diverse backgrounds and not speaking for any organization, who have found common ground around teleological concepts, including intelligent design. We think these concepts have real potential to generate insights about our reality that are being drowned out by political advocacy from both sides. We hope this blog will provide a small voice that helps rectify this situation.
Website dedicated to comparing scenes from the "Inherit the Wind" movie with factual information from actual Scopes Trial. View 37 clips from the movie and decide for yourself if this movie is more fact or fiction.
Don Cicchetti blogs on: Culture, Music, Faith, Intelligent Design, Guitar, Audio
Australian biologist Stephen E. Jones maintains one of the best origins "quote" databases around. He is meticulous about accuracy and working from original sources.
Most guys going through midlife crisis buy a convertible. Austrialian Stephen E. Jones went back to college to get a biology degree and is now a proponent of ID and common ancestry.
Complete zipped downloadable pdf copy of David Stove's devastating, and yet hard-to-find, critique of neo-Darwinism entitled "Darwinian Fairytales"
Intelligent Design The Future is a multiple contributor weblog whose participants include the nation's leading design scientists and theorists: biochemist Michael Behe, mathematician William Dembski, astronomer Guillermo Gonzalez, philosophers of science Stephen Meyer, and Jay Richards, philosopher of biology Paul Nelson, molecular biologist Jonathan Wells, and science writer Jonathan Witt. Posts will focus primarily on the intellectual issues at stake in the debate over intelligent design, rather than its implications for education or public policy.
A Philosopher's Journey: Political and cultural reflections of John Mark N. Reynolds. Dr. Reynolds is Director of the Torrey Honors Institute at