Document Detail


The predominant form in which neurofilament subunits undergo axonal transport varies during axonal initiation, elongation, and maturation.
MedLine Citation:
PMID:  11124711     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The forms in which neurofilament (NF) subunits undergo axonal transport is controversial. Recent studies from have provided real-time visualization of the slow axonal transport of NF subunits by transfecting neuronal cultures with constructs encoding green fluorescent protein (GFP)-conjugated NF-M subunits. In our studies in differentiated NB2a/d1 cells, the majority NF subunits underwent transport in the form of punctate NF precursors, while studies in cultured neurons have demonstrated transport of NF subunits in predominantly filamentous form. Although different constructs were used in these studies, transfection of the same cultured neurons with our construct yielded the filamentous pattern observed by others, while transfection of our cultures with their construct generated punctate structures, confirming that the observed differences did not reflect variances in assembly-competence among the constructs. Manipulation of intracellular kinase, phosphatase, and protease activities shifted the predominant form of GFP-conjugated subunits between punctate and filamentous, confirming, as shown previously for vimentin, that punctate structures represent precursors for intermediate filament formation. Since these prior studies were conducted at markedly differing neuronal differentiation states, we tested the alternate hypothesis that these differing results reflected developmental alterations in NF dynamics that accompany various stages of neuritogenesis. We conducted time-course analyses of transfected NB2a/d1 cells, including monitoring of transfected cells over several days, as well as transfecting cells at varying intervals prior to and following induction of differentiation and axonal neurite outgrowth. GFP-conjugated subunits were predominantly filamentous during the period of most robust axonal outgrowth and NF accumulation, and presented a mixed profile of punctate and filamentous forms prior to neuritogenesis and following the developmental slowing of neurite outgrowth. These analyses demonstrate that NF subunits are capable of undergoing axonal transport in multiple forms, and that the predominant form in which NF subunits undergo axonal transport varies in accord with the rate of axonal elongation and accumulation of NFs within developing axons.
Authors:
J T Yabe; W K Chan; T M Chylinski; S Lee; A F Pimenta; T B Shea
Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, Non-P.H.S.; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Cell motility and the cytoskeleton     Volume:  48     ISSN:  0886-1544     ISO Abbreviation:  Cell Motil. Cytoskeleton     Publication Date:  2001 Jan 
Date Detail:
Created Date:  2001-01-10     Completed Date:  2001-01-25     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  8605339     Medline TA:  Cell Motil Cytoskeleton     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  61-83     Citation Subset:  IM    
Affiliation:
Center for Cellular Neurobiology and Neurodegeneration Research, Department of Biological Sciences, University of Massachusetts-Lowell, Lowell, USA.
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MeSH Terms
Descriptor/Qualifier:
Animals
Axonal Transport / physiology*
Axons / physiology*
Cell Differentiation
Cells, Cultured
Cysteine Proteinase Inhibitors / pharmacology
Cytoskeleton / drug effects,  metabolism
Densitometry
Detergents / pharmacology
Dipeptides / pharmacology
Green Fluorescent Proteins
Immunohistochemistry
Luminescent Proteins / metabolism
Neurofilament Proteins / chemistry,  genetics,  metabolism*
Neurons / cytology,  physiology*
Nocodazole / pharmacology
Protein Subunits
Rats
Recombinant Fusion Proteins / metabolism
Superior Cervical Ganglion / cytology
Transfection
Chemical
Reg. No./Substance:
0/Cysteine Proteinase Inhibitors; 0/Detergents; 0/Dipeptides; 0/Luminescent Proteins; 0/Neurofilament Proteins; 0/Protein Subunits; 0/Recombinant Fusion Proteins; 117591-20-5/calpeptin; 147336-22-9/Green Fluorescent Proteins; 31430-18-9/Nocodazole

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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