scholarly journals Fast axonal transport of kinesin in the rat visual system: functionality of kinesin heavy chain isoforms.

1995 ◽  
Vol 6 (1) ◽  
pp. 21-40 ◽  
Author(s):  
R G Elluru ◽  
G S Bloom ◽  
S T Brady

The mechanochemical ATPase kinesin is thought to move membrane-bounded organelles along microtubules in fast axonal transport. However, fast transport includes several classes of organelles moving at rates that differ by an order of magnitude. Further, the fact that cytoplasmic forms of kinesin exist suggests that kinesins might move cytoplasmic structures such as the cytoskeleton. To define cellular roles for kinesin, the axonal transport of kinesin was characterized. Retinal proteins were pulse-labeled, and movement of radiolabeled kinesin through optic nerve and tract into the terminals was monitored by immunoprecipitation. Heavy and light chains of kinesin appeared in nerve and tract at times consistent with fast transport. Little or no kinesin moved with slow axonal transport indicating that effectively all axonal kinesin is associated with membranous organelles. Both kinesin heavy chain molecular weight variants of 130,000 and 124,000 M(r) (KHC-A and KHC-B) moved in fast anterograde transport, but KHC-A moved at 5-6 times the rate of KHC-B. KHC-A cotransported with the synaptic vesicle marker synaptophysin, while a portion of KHC-B cotransported with the mitochondrial marker hexokinase. These results suggest that KHC-A is enriched on small tubulovesicular structures like synaptic vesicles and that at least one form of KHC-B is predominantly on mitochondria. Biochemical specialization may target kinesins to appropriate organelles and facilitate differential regulation of transport.

1999 ◽  
Vol 10 (11) ◽  
pp. 3717-3728 ◽  
Author(s):  
MaryAnn Martin ◽  
Stanley J. Iyadurai ◽  
Andrew Gassman ◽  
Joseph G. Gindhart ◽  
Thomas S. Hays ◽  
...  

In axons, organelles move away from (anterograde) and toward (retrograde) the cell body along microtubules. Previous studies have provided compelling evidence that conventional kinesin is a major motor for anterograde fast axonal transport. It is reasonable to expect that cytoplasmic dynein is a fast retrograde motor, but relatively few tests of dynein function have been reported with neurons of intact organisms. In extruded axoplasm, antibody disruption of kinesin or the dynactin complex (a dynein activator) inhibits both retrograde and anterograde transport. We have tested the functions of the cytoplasmic dynein heavy chain (cDhc64C) and the p150Glued(Glued) component of the dynactin complex with the use of genetic techniques in Drosophila.cDhc64C and Glued mutations disrupt fast organelle transport in both directions. The mutant phenotypes, larval posterior paralysis and axonal swellings filled with retrograde and anterograde cargoes, were similar to those caused by kinesin mutations. Why do specific disruptions of unidirectional motor systems cause bidirectional defects? Direct protein interactions of kinesin with dynein heavy chain and p150Glued were not detected. However, strong dominant genetic interactions between kinesin, dynein, and dynactin complex mutations in axonal transport were observed. The genetic interactions between kinesin and either Glued orcDhc64C mutations were stronger than those betweenGlued and cDhc64C mutations themselves. The shared bidirectional disruption phenotypes and the dominant genetic interactions demonstrate that cytoplasmic dynein, the dynactin complex, and conventional kinesin are interdependent in fast axonal transport.


2003 ◽  
Vol 161 (1) ◽  
pp. 55-66 ◽  
Author(s):  
Chun-Hong Xia ◽  
Elizabeth A. Roberts ◽  
Lu-Shiun Her ◽  
Xinran Liu ◽  
David S. Williams ◽  
...  

To test the hypothesis that fast anterograde molecular motor proteins power the slow axonal transport of neurofilaments (NFs), we used homologous recombination to generate mice lacking the neuronal-specific conventional kinesin heavy chain, KIF5A. Because null KIF5A mutants die immediately after birth, a synapsin-promoted Cre-recombinase transgene was used to direct inactivation of KIF5A in neurons postnatally. Three fourths of such mutant mice exhibited seizures and death at around 3 wk of age; the remaining animals survived to 3 mo or longer. In young mutant animals, fast axonal transport appeared to be intact, but NF-H, as well as NF-M and NF-L, accumulated in the cell bodies of peripheral sensory neurons accompanied by a reduction in sensory axon caliber. Older animals also developed age-dependent sensory neuron degeneration, an accumulation of NF subunits in cell bodies and a reduction in axons, loss of large caliber axons, and hind limb paralysis. These data support the hypothesis that a conventional kinesin plays a role in the microtubule-dependent slow axonal transport of at least one cargo, the NF proteins.


Genetics ◽  
1996 ◽  
Vol 144 (3) ◽  
pp. 1075-1085 ◽  
Author(s):  
Daryl D Hurd ◽  
William M Saxton

Abstract Previous work has shown that mutation of the gene that encodes the microtubule motor subunit kinesin heavy chain (Khc) in Drosophila inhibits neuronal sodium channel activity, action potentials and neurotransmitter secretion. These physiological defects cause progressive distal paralysis in larvae. To identify the cellular defects that cause these phenotypes, larval nerves were studied by light and electron microscopy. The axons of Khc mutants develop dramatic focal swellings along their lengths. The swellings are packed with fast axonal transport cargoes including vesicles, synaptic membrane proteins, mitochondria and prelysosomal organelles, but not with slow axonal transport cargoes such as cytoskeletal elements. Khc mutations also impair the development of larval motor axon terminals, causing dystrophic morphology and marked reductions in synaptic bouton numbers. These observations suggest that as the concentration of maternally provided wild-type KHC decreases, axonal organelles transported by kinesin periodically stall. This causes organelle jams that disrupt retrograde as well as anterograde fast axonal transport, leading to defective action potentials, dystrophic terminals, reduced transmitter secretion and progressive distal paralysis. These phenotypes parallel the pathologies of some vertebrate motor neuron diseases, including some forms of amyotrophic lateral sclerosis (ALS), and suggest that impaired fast axonal transport is a key element in those diseases.


2006 ◽  
Vol 173 (4) ◽  
pp. 545-557 ◽  
Author(s):  
Elizabeth E. Glater ◽  
Laura J. Megeath ◽  
R. Steven Stowers ◽  
Thomas L. Schwarz

Mitochondria are distributed within cells to match local energy demands. We report that the microtubule-dependent transport of mitochondria depends on the ability of milton to act as an adaptor protein that can recruit the heavy chain of conventional kinesin-1 (kinesin heavy chain [KHC]) to mitochondria. Biochemical and genetic evidence demonstrate that kinesin recruitment and mitochondrial transport are independent of kinesin light chain (KLC); KLC antagonizes milton's association with KHC and is absent from milton–KHC complexes, and mitochondria are present in klc −/− photoreceptor axons. The recruitment of KHC to mitochondria is, in part, determined by the NH2 terminus–splicing variant of milton. A direct interaction occurs between milton and miro, which is a mitochondrial Rho-like GTPase, and this interaction can influence the recruitment of milton to mitochondria. Thus, milton and miro are likely to form an essential protein complex that links KHC to mitochondria for light chain–independent, anterograde transport of mitochondria.


1994 ◽  
Vol 127 (4) ◽  
pp. 1041-1048 ◽  
Author(s):  
P A Pesavento ◽  
R J Stewart ◽  
L S Goldstein

This paper describes the molecular and biochemical properties of KLP68D, a new kinesin-like motor protein in Drosophila melanogaster. Sequence analysis of a full-length cDNA encoding KLP68D demonstrates that this protein has a domain that shares significant sequence identity with the entire 340-amin acid kinesin heavy chain motor domain. Sequences extending beyond the motor domain predict a region of alpha-helical coiled-coil followed by a globular "tail" region; there is significant sequence similarity between the alpha-helical coiled-coil region of the KLP68D protein and similar regions of the KIF3 protein of mouse and the KRP85 protein of sea urchin. This finding suggests that all three proteins may be members of the same family, and that they all perform related functions. KLP68D protein produced in Escherichia coli is, like kinesin itself, a plus-end directed microtubule motor. In situ hybridization analysis of KLP68D RNA in Drosophila embryos indicates that the KLP68D gene is expressed primarily in the central nervous system and in a subset of the peripheral nervous system during embryogenesis. Thus, KLP68D may be used for anterograde axonal transport and could conceivably move cargoes in fly neurons different than those moved by kinesin heavy chain or other plus-end directed motors.


1990 ◽  
Vol 68 (10) ◽  
pp. 1317-1321 ◽  
Author(s):  
R. D. Kilgour ◽  
K. Gardiner ◽  
P. F. Gardiner

Phosphofructokinase activity was measured in the sciatic nerve of streptozotocin-induced diabetic and nondiabetic rats. Average steady-state phosphofructokinase activity was obtained from three consecutive segments of the mid-femoral region in the left sciatic nerve in both diabetic (4 and 24 weeks) and nondiabetic, age-matched animals. Over time, phosphofructokinase activity significantly decreased (p < 0.05) with diabetes, with no effect demonstrated within similar age-groups. The accumulation of phosphofructokinase activity was accomplished by ligating the mid-femoral region of the right sciatic nerve for 24 h. Anterograde and retrograde axonal transport of phosphofructokinase was measured in the 3-mm segment proximal and distal to the ligature, respectively. There was a trend (p = 0.0627) towards a decline in net proximal accumulation (mean proximal minus mean background) with age. Net distal (mean distal minus mean background) activity declined by 80% (p < 0.05) in the control group between 4 and 24 weeks of the diabetic state. However, diabetic animals did not experience the same age-related decline in retrograde transport. The findings suggest that diabetes affects the age-associated evolution of retrograde transport, presumably a reflection of the neuropathy occurring in the distal axon branches, without altering anterograde transport to any appreciable extent.Key words: phosphofructokinase, slow axonal transport, sciatic nerve, diabetes, streptozotocin.


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