Notes

Axon transport
-Neurons are unique in their size and polarized morphology
-Axons in head receive signals and transfer them down to the tail dendrites
-Motor neuron: can stretch up to 1m
->Electrically active cell must last as long as your life
Many cargos are actively transported through axons and dendrites
-Mitochondria
-Endosomes
-Lysosomes
-Autophagosomes
Each cargo moves in a unique manner, distinctly characterized by speed, directionality, pauses, stops, and restarts
-How long can it take
-> Fast Axonal Transport Time: (i.e. vesicular transport)
-> 4 minutes, 2 hours, 3 hours, 2.5 days
-Microtubule motor proteins drive l.ong-range motility along the polarized microtubule cytoskeleton
-> microtubules are criss-crossed in the length of the neuron (not one long microtubule)
Kinesin have two heads that interact with each other and cause it to "walk" along the microtubule
-Specific proteins that activate kinesin proteins
-Mitchondria become increasingly immotile as neurons age
->Tracking of mitochondria in explants and in vivo
-Immotile mitochonrdria often localize at presynaptic siters
WHY DO MITOCHONDRIA NEED TO MOVE?
-Neuromuscular junction is where there is a lot of energy and needs local power generators delivering energy where you need it
-Mitochondria are found in localized areas to allow for a quick supply of energy
-Mitochondria is ussed as a calcium buffer as well

Localized mitochondria provide:
-Localized production of ATP
-Localized buffering of CA2+

How is mitochondrial transport regulated?

The anchor: Syntaphilin tethers axonal mitochondria
-> acts as a mito hondrial docking protein in axons but not dendrite.
-> lot of syntaphilin markedly increases mitochondrial activity
Autophagy: A lysosomal degradation pathway to eliminate long-lived and damaged protein/organelles
Autophagy maintains the quality and homeostasis of intracellular environment
-Dynein and kinesin motors co-purify with autophagosomes