Question

Students in a neurobiology laboratory are expected to observe five neuron cultures, each of which is preferentially overexpressing one particular type of microtubule-associated protein. Which of the following phenotypes would best allow the students to identify the Tau-overexpressing neurons?

A. Enhanced stability of microtubules
B. Increased microtubule nucleation
C. Formation of microtubule bundles
D. Disruption of actin filaments

Answer 1

To identify Tau-overexpressing neurons, students should look for enhanced microtubule stability, since Tau normally stabilizes microtubules when it's phosphorylated, but pathological hyper-phosphorylation leads to instability and tangle formation.

Step-by-step explanation:

To identify the Tau-overexpressing neurons among the neuron cultures, students should look for the phenotype showing enhanced stability of microtubules. Under normal conditions, Tau, a Microtubule-Associated Protein (MAP-T), is phosphorylated, allowing it to bind to and stabilize microtubules. However, in pathological conditions such as Alzheimer's Disease, when Tau becomes hyper-phosphorylated, it alters its conformation and no longer stabilizes microtubules, leading to disassembly and the formation of neurofibrillary tangles. Therefore, the presence of Tau-overexpressing neurons can be inferred from stabilized microtubules, as the disrupted Tau would result in the opposite effect of microtubule instability.