The long term goal of this project is to characterize the structure and function of P-57, a novel calmodulin (CaM) binding protein from brain. We have recently purified P-57 to apparent homogeneity from bovine cerebral cortex membranes. In contrast to other CaM binding proteins, P-57 apparently has higher affinity for CaM in the absence of bound Ca2+ than in its presence and Ca2+ causes the release of CaM from P-57. It is hypothesized that P-57 may function to bind CaM at some local site within the cell and release CaM in response to increases in free Ca2+.
The specific aims of this project include quantitation of binding between P-57 and CaM in the presence and absence of Ca2+, determining if P-57 interacts with other polypeptides in brain, examination of the tissue distribution of P-57, characterization of the physical properties of P-57, characterization of cAMP dependent protein kinase catalyzed phosphorylation of P-57, and determination of the influence of phosphorylation on the affinity of P-57 for CaM. Homogeneous P-57 in mg quantities, anti-P57 rabbit polyclonal antibodies, and fluorescent labeled CaM derivatives are currently available for the proposed experiments.
|Liu, Y; Fisher, D A; Storm, D R (1994) Intracellular sorting of neuromodulin (GAP-43) mutants modified in the membrane targeting domain. J Neurosci 14:5807-17|
|Liu, Y; Fisher, D A; Storm, D R (1993) Analysis of the palmitoylation and membrane targeting domain of neuromodulin (GAP-43) by site-specific mutagenesis. Biochemistry 32:10714-9|
|Chapman, E R; Alexander, K; Vorherr, T et al. (1992) Fluorescence energy transfer analysis of calmodulin-peptide complexes. Biochemistry 31:12819-25|
|Chapman, E R; Estep, R P; Storm, D R (1992) Palmitylation of neuromodulin (GAP-43) is not required for phosphorylation by protein kinase C. J Biol Chem 267:25233-8|
|Chapman, E R; Au, D; Alexander, K A et al. (1991) Characterization of the calmodulin binding domain of neuromodulin. Functional significance of serine 41 and phenylalanine 42. J Biol Chem 266:207-13|
|Apel, E D; Litchfield, D W; Clark, R H et al. (1991) Phosphorylation of neuromodulin (GAP-43) by casein kinase II. Identification of phosphorylation sites and regulation by calmodulin. J Biol Chem 266:10544-51|
|Chapman, E R; Au, D; Nicolson, T A et al. (1991) Mutagenesis of the calmodulin binding domain of neuromodulin. Prog Brain Res 89:37-44|
|Liu, Y C; Chapman, E R; Storm, D R (1991) Targeting of neuromodulin (GAP-43) fusion proteins to growth cones in cultured rat embryonic neurons. Neuron 6:411-20|
|Liu, Y C; Storm, D R (1991) Expression of a neuromodulin-beta-galactosidase fusion protein in primary cultured neurons and its accumulation in growth cones. Mol Cell Biochem 104:29-34|
|Apel, E D; Byford, M F; Au, D et al. (1990) Identification of the protein kinase C phosphorylation site in neuromodulin. Biochemistry 29:2330-5|
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