Lecture 6--the cytoskeleton-1

The right one or the left the older subunits are

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: d first, theyve been in polymer longer so longer time to be hydrolzed. now theyre all being GDP bound, and that causes the protofilament to nbe weakr; protofilament curves, both curvid and GDP binding reduce the affinitiy of the dimers to eachtohers so they start to fall off; grpwig and shrinking on same end; (+) side stablized by gamma tubulin Figure 16-16b Molecular Biology of the Cell (© Garland Science 2008) dark green: GTP bound dimers stability of microtubul es canbe affected by other proteins when addig new dimers. start on right side; over time, those on the plus end start to hydrolyze as long as the ones on the end are GTP bound theyare stable and can light green circles: GDP bound continue to grow dimers hydroysis can catch up to the end, cap is lost, protofilaments droop, individual dimers fall off, andget a vary rapid shrinkage pf the microtubule, consquenc e caled catastrophy (shrnking when cap is gone). as it shrinks, dimers are released, and those dimers can exchange GDP for GTP and theyre ready to add again to the (+) end) dynamic instability: important for function of tubulin; can mess up tubulinwith things that stabilize and destabilize them. taxol, chemotherapy drug, actually stabilizes microtubules but it is preventing the cycle of growth and catastrophy. Figure 16-16a Molecular Biology of the Cell (© Garland Science 2008) Microtubule associated proteins (MAPS1-4) they can : promote drpolimerization, but often think of them as providing stability. MAP2 cell that is completing mytosis has a spindle it has to take apart. MAP2 microtubule • • MAPs can function as cross-bridges connecting microtubules. They can affect microtubule rigidity and assembly rate. example of cell expressing lots of MAP2, one thing does is maintain the space between microtubules; it is helping stablize and arrange them Figure 16-41 Molecular Biology of the Cell (© Garland Science 2008) tau is protein with strongest association to alzeihmers disease. mutation causes TAU to aggregate. aggregated TAU clogs axons so that thinga can...
View Full Document

Ask a homework question - tutors are online