PHOSPHORYLATION OF THE CYTOSKELETON IN NEURONAL GROWTH

Project: Research project

Description

This project will continue our investigation of the role of protein
phosphorylation in regulating neuronal function. The biochemical mechanisms
controlling neurite extension will be examined in NGF treated PC12 cells.
Recent research in this laboratory has identified a novel proline-directed
protein kinase activated by NGF treatment. The minimal recognition sequence
for this kinase is --X-Ser/Thr-Pro-X--. Many neuron specific structural
proteins including synapsin, tau, microtubule associated proteins, and
neurofilament proteins contain this consensus sequence and several have
been identified as in vitro substrates of this novel kinase. Since these
proteins are substrates for more than one protein kinase and contain
multiple phosphorylation sites, the specific sites of phosphorylation will
be isolated and sequenced. The phosphorylation sites will be localized in
the proteins that have a known sequence. These studies also will investigate the in situ phosphorylation of the
cytoskeletal apparatus during neurite outgrowth. 32p-orthophosphate
labelled PC12 cells will be treated with NGF and key cytoskeletal proteins
will be examined for phosphate incorporation. Specific proteins including
TH, synapsin, Tau, MAP's, and neurofilament proteins will be examined for
their ability to incorporate phosphate. Since these same proteins are
phosphorylated in situ following NGF treatment, the specific
phosphorylation sites will be identified to examine the role of PDPK in
mediating NGF induced neurite outgrowth. Other work in our laboratory has
established that sphingosine, a specific inhibitor of PK C, blocks neurite
extension. The exact role of PK C in modulating neurite extension will be
further investigated in regard to specific substrates and sites
phosphorylated during NGF induced neurite outgrowth. The relationship
between PK C and PDPK mediated protein phosphorylation in regulating
neurite extension will be examined. Understanding how neurons use protein phosphorylation mechanisms to form
neurites may identify fundamental molecular mechanisms that underlie the
pathogenesis of Alzheimer's disease, since the PDPK substrate proteins
found in the neurofibrillary tangles have abnormal phosphorylation
patterns.
StatusFinished
Effective start/end date8/1/907/31/97

Funding

  • National Institutes of Health
  • National Institutes of Health
  • National Institutes of Health
  • National Institutes of Health
  • National Institutes of Health
  • National Institutes of Health

Fingerprint

Nerve Growth Factor
Cytoskeleton
Phosphorylation
Growth
Synapsins
Proteins
Phosphotransferases
PC12 Cells
Neurites
Phosphates
Neurofilament Proteins
Neurons
tau Proteins
Neurofibrillary Tangles
Sphingosine
Aptitude
Microtubule-Associated Proteins
Consensus Sequence
Proline
Protein Kinases

ASJC

  • Medicine(all)
  • Neuroscience(all)