Organelle transport is vital for the development and maintenance of axons, in which distances between sites organelle biogenesis, function, recycling or degradation can be vast. Movement mitochondria axons serve as a general model how all organelles move: are easy to identify, they move along both microtubule actin tracks, pause change direction, their modulated response physiological signals. However, distinguished from other axonal by complexity movement unique functions aerobic...

A large body of evidence indicates that microtubules (MTs) conduct organelle transport in axons, but recent studies on extruded squid axoplasm have suggested actin microfilaments (MFs) may also play a role this process. To investigate the separate contributions to each class cytoskeletal element intact vertebrate we monitored mitochondrial movements chick sympathetic neurons experimentally manipulated eliminate MTs, MFs, or both. First, grew continuous presence of: (a) cytochalasin E create...

ABSTRACT Although small molecules such as ATP diffuse freely in the cytosol, many types of cells nonetheless position their mitochondria regions intense consumption. We reasoned that highly elongated axonal processes growing neurons culture, active growth cone would form a focus consumption so distant from cell body to require positioning nearby via regulated transport. To test this hypothesis, we quantified distribution and transport behavior live, aerobically respiring chick sympathetic...

Vigorous transport of cytoplasmic components along axons over substantial distances is crucial for the maintenance neuron structure and function. The mitochondria, which serves to distribute mitochondrial functions in a dynamic non-uniform fashion, has attracted special interest recent years following discovery functional connections among microtubules, motor proteins their influences on neurodegenerative diseases. Although that drive movement are now well characterized, mechanisms by...

Cellular homeostasis in neurons requires that the synthesis and anterograde axonal transport of protein membrane be balanced by their degradation retrograde transport. To address nature regulation cultured sympathetic neurons, I analyzed behavior, composition, ultrastructure a class large, phase-dense organelles whose movement has been shown to influenced growth (Hollenbeck, P. J., D. Bray. 1987. J. Cell Biol. 105:2827-2835). In actively elongating axons these underwent both movements,...

Organelle acidification is an essential element of the endosomal-lysosomal pathway, but our understanding mechanisms underlying progression through this pathway has been hindered by absence adequate methods for quantifying intraorganelle pH. To address problem in neurons, we developed a direct quantitative method accurately determining pH endocytic organelles live cells. In report, demonstrate that ratiometric fluorescent indicator 8-hydroxypyrene-1,3,6-trisulfonic acid (HPTS) most...

ABSTRACT Regional regulation of organelle transport seems likely to play an important role in establishing and maintaining distinct axonal dendritic domains neurons, managing differences local metabolic demands. In addition, known microtubule polarity organization between axons dendrites along with the directional selectivity microtubulebased motor proteins suggest that patterns may differ these two process types. To test this hypothesis, we compared movement different classes regions...

Neurons transport and position mitochondria using a combination of saltatory, bidirectional movements stationary docking. Axonal move along microtubules (MTs) kinesin dynein motors, but actin myosin also play poorly defined role in their traffic. To ascertain this role, we have used RNA interference (RNAi) to deplete specific motors cultured <i>Drosophila</i> neurons quantified the effects on mitochondrial motility. We produced fly strain expressing <i>Caenorhabditis elegans</i> transporter...

An antiserum which binds kinesin specifically on Western blots was used to determine the distribution and abundance of chicken by correlated immunoblotting immunolocalization. Quantitative showed that varied widely in different cell tissue types, from 0.039% total protein epidermal fibroblasts 0.309% sympathetic neurons; types examined, only red blood cells lacked detectable kinesin. The molar ratio tubulin/kinesin over a narrower range. To analyze intracellular kinesin, cultured were...

Abstract Mitochondria are widely distributed via regulated transport in neurons, but their sites of biogenesis remain uncertain. Most mitochondrial proteins encoded the nuclear genome, and evidence has suggested that DNA (mtDNA) replication occurs mainly or entirely cell body. However, it also become clear nuclear‐encoded can be translated axon components machinery reside there as well. We assessed directly whether mtDNA occur axons chick peripheral neurons labeled with...

Neurons concentrate mitochondria at sites in the cell that have a high demand for ATP and/or calcium buffering. To accomplish this, mitochondrial transport and docking are thought to respond intracellular signaling pathways. However, might also function by locally modulating activity. We tested this hypothesis measuring membrane potential of individual throughout axons chick sensory neurons using dye tetramethylrhodamine methylester (TMRM). found no difference TMRM...

Mitochondria are concentrated in regions of the neuron where demand for mitochondrial function is high, such as nodes Ranvier, synapses, and active growth cones. Does transport respond to changes neuronal energy consumption architecture, or does it precede perhaps predict them? We have used axon determination, elongation, alternating branch hippocampal neurons analyze cellular cues that control traffic. During stage 2–3 transition, when one minor process becomes accelerates its growth,...

In neurons, the normal distribution and selective removal of mitochondria are considered essential for maintaining functions large asymmetric cell its diverse compartments. Parkin, a E3 ubiquitin ligase associated with familial Parkinson's disease, has been implicated in mitochondrial dynamics cells including neurons. However, it is not clear how Parkin turnover vivo, or whether Parkin-dependent events life cycle occur all neuronal Here, using live Drosophila nervous system, we investigated...

Maintenance of healthy mitochondria is crucial in cells, such as neurons, with high metabolic demands, and dysfunctional are thought to be selectively degraded. Studies chemically uncoupled cells have implicated PINK1 mitochondrial kinase, Parkin E3 ubiquitin ligase targeting depolarized for degradation. However, the role PINK1/Parkin pathway turnover unclear nervous system under normal physiological conditions, we understand little about changes that occur life cycle when disrupted. Here,...

Despite the wealth of information about endocytic pathways in non-neuronal cells, little is known these crucial sorting, recycling, and degradative neurons. In this report, we analyzed detail dynamic steady-state organization endocytically derived organelles as they progress through endosomal-lysosomal pathway axons live cultured sympathetic By ratiometric imaging neurons labeled with pH indicator 8-hydroxypyrene-1,3,6-trisulfonic acid (HPTS), demonstrate a trimodal frequency distribution...

The motor protein kinesin is implicated in organelle movement toward the plus ends of microtubules, but little known about its interaction with membranes or physiological role phosphorylation and associated kinectin seen neurons vivo (Hollenbeck, P. J. (1993) Neurochem. 60, 2265-2275). Here we have demonstrated that heavy chain (KHC), light chain, isolated from chick brain sympathetic exist several isoelectric forms. Metabolic labeling followed by phosphatase treatment showed these are...

Abstract: The microtubule‐based motor protein kinesin is thought to drive anterograde organelle transport in axons, but nothing known about how its force‐generating activity or organelle‐binding properties are regulated. Studies other motility systems suggest that phosphorylation a reasonable candidate for this function. I report here the heavy chain (HC) and light (LC), as well 160‐kDa kinesin‐associated kinectin, phosphorylated vivo cultures of chick sympathetic neurons PC12 cells labeled...

Many axons carry out the synthesis of macromolecules independent their cell bodies but nature, organization and magnitude axonal protein remain unclear. We have examined these features in chick sympathetic neurons culture. In situ hybridization showed that poly(A) mRNA is abundant non-uniformly distributed nearly all axons. The specific transcripts for beta-actin actin-depolymerizing factor (ADF) were also present axons, with an approximately hundredfold higher concentration growth cones,...