S9 Cell Biology of the nervous system Flashcards
intermediate filaments function
strengthen cells against mechanical stress
Microtubules
structural polarity, dynamic instability, tracks for organelle traffic
Microtubule-associated proteins
differentially distributed in neurons (Map2- cell bodies) (tau-axons)
Actin and microtubules important in growth cone
Actin in peripheral, highly dynamic, treadmill. Growth cone looking for right location, looking for signals. Microtubules further back helping with structure and driving force in growth cone.
protrusion
Actin is assembled & turned over along the leading edge
Microtubules explore the periphery
Weak adhesion receptor coupling
Adhesion/signaling
Adhesion/signaling
Contact with adhesive substrate
Stimulates adhesion receptor clustering and signaling
Exploration by microtubules
Engorgement /stretching /traction /consolidation
Strong adhesion receptor coupling
Forward movement of actin
Actin direct microtubules towards adhesion sites
inhibition of fast axonal transport results in
loss of synaptic function
“Dying-back” degeneration of axons
Early pathogenic events – ALS, Huntington’s disease, Alzheimer’s disease, Parkinson’s disease
axonal transport damage
In alzeimer’s disease: can have hyperphosporylation of tau so it can’t bind and stabilize microtubules. Leads to breakdown of proper axonal transport.
b: Micortubules can be organized. But have problem that results in motor proteins being unuable to bind to cargo.
Huntington’s disease. C: Deactylation of motor proteins ,they can’t bind to road. D. issues with motor proteins being able to load and use roads.
Point: process is important. Many different players. In these different neural disorders, one protien can become problematic resulting in overall transport disfunction.
most mtDNA defects are
heteroplasmic
