Phosphorylation Modulates Calpain-Mediated Proteolysis and Calmodulin Binding of the 200-kDa and 160-kDa Neurofilament Proteins |
| |
| Authors: | Jeffrey A. Greenwood,Juan C. Troncoso,&dagger ,Anthony C. Costello,Gail V. W. Johnson |
| |
| Affiliation: | Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, Alabama;Neuropathology Laboratory, The Johns Hopkins University School of Medicine, Baltimore, Maryland, U.S.A.;Departments of Pathology and Neurology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, U.S.A. |
| |
| Abstract: | Abstract: The effects of enzymatic dephosphorylation on neurofilament interaction with two calcium-binding proteins, calpain and calmodulin, were examined. Dephosphorylation increased the rate and extent of 200-kDa neurofilament protein proteolysis by calpain. In contrast, dephosphorylation of the 160-kDa neurofilament protein did not alter the rate or extent of calpain proteolysis. However, the calpain-induced breakdown products of native and dephosphorylated 160-kDa neurofilament protein were different. Dephosphorylation did not change the proteolytic rate, extent, or breakdown products of the 68-kDa neurofilament protein. Calmodulin binding to the purified individual 160- and 200-kDa neurofilament proteins was increased following dephosphorylation. These results suggest that phosphorylation may regulate the metabolism and function of neurofilaments by modulating interactions with the calcium-activated proteins calpain and calmodulin. |
| |
| Keywords: | Neurofilament proteins Dephosphorylation Calpain Calmodulin Calcium - activated proteins |
|
|
