Growing | Nongrowing | Paired t test | |
---|---|---|---|
Into branch | 7.15 | 3.23 | p = 0.024 |
Out of branch | 2.95 | 4.18 | p = 0.320 |
Paired t test | p = 0.003 | p = 0.414 | n = 14 cells |
Mitochondria are selectively sorted into growing branches but do not selectively exit from nongrowing branches. The numbers of mitochondria moving through axonal branch points per hour were measured for the four possible classes of transport: mitochondria moving out of the main axon and into the growing branch, those moving from the main axon into the nongrowing branch, those exiting the growing branch and returning to the main axon, and those exiting the nongrowing branch to return to the main axon. The mean values shown indicate that mitochondria moving anterogradely and entering a branch point have more than twice the probability of sorting into the growing branch than the nongrowing branch, but mitochondria exit both branches at similar rates (n = 14 branched neurons).