Question

Microtubules are polymerized from tubulin alpha beta heterodimers. What is a major difference between the alpha and beta forms of tubulin?

-alpha tubulin binds ATP while beta tubulin binds GTP
-alpha tubulin is found only in mitotic spindle microtubules and not interphase microtubules
-beta tubulin is a type of intermediate filament while alpha tubulin is related to actin
-both alpha tubulin and beta tubulin bind to GTP, but only beta tubulin hydrolyzes GTP

Answer 1

Alpha and beta tubulin both bind to GTP, but only beta tubulin has the ability to hydrolyze GTP, which is crucial for the dynamic instability of microtubules in cellular processes.

Step-by-step explanation:

The major difference between alpha and beta tubulin is that both bind to GTP, but only beta tubulin hydrolyzes GTP. Alpha and beta-tubulin form heterodimers, which polymerize to create the structure of microtubules. Microtubules themselves play crucial roles in maintaining cell shape, enabling intracellular transport, and facilitating cell division. Nonetheless, while alpha-tubulin is permanently bound to a GTP molecule that is non-exchangeable and does not hydrolyze, beta-tubulin binds GTP that can be hydrolyzed to GDP. This GTP hydrolysis by beta-tubulin is essential for the dynamic instability of microtubules, allowing them to rapidly assemble and disassemble. This dynamic process is critical for their functions during cellular events such as mitosis.