This project is divided into four sections, all of which share a common focus on the role of calmodulin and calcium as regulators of vesicle functions present in nerve endings and of the structural protein molecules around vesicles that participate in the attachment and/or fusion of these organelles with the plasma membrane. The first series of studies focuses on the molecular interactions of clathrin's polypeptides with its associated proteins (CAPs), with the vesicle membrane and with calmodulin in conferring calcium sensitivity to these interactions. For these studies we use affinity-binding chromatography and chemical cross-linkers between amino acid residues of bound proteins. The second set of studies concerns the process of phosphorylation in coated and synaptic vesicles. The identity of the phosphorylated proteins and of the protein kinases found in synaptic and coated vesicles will be determined by their calcium-calmodulin activation patterns, autoradiography of labeled polypeptides resolved after one- or two-dimensional (gel) electrophoresis, and comparison of kinase properties after separation from their corresponding vesicle population. The third set of studies will focus on the calcium/calmodulin-dependent phospholipase A2 activity in both types of vesicles and in synaptosomal membrane preparations. Enzymatic activity will be measured using specifically labeled precursors and the products formed, separated and identified by thin-layer chromatography and/or high-performance liquid chromatography. These enzymes appear to destabilize vesicle membrane, facilitating vesicle aggregation and possibly fusion of vesicles, phenomena that will be examined by light scattering and electron microscopy. The final section of the project will address the separation of these proteins, preparation of specific polyvalent and monoclonal antibodies, and their subcellular localization in brain tissue and cultured cells. We believe that deficient innervation leads to inefficient function, e.g., atrophic muscle disorders. A better understanding of how nerve endings function may be attained by elucidation of the molecules and their interactions in these organelles.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS012467-12
Application #
3394875
Study Section
Neurology B Subcommittee 1 (NEUB)
Project Start
1978-06-01
Project End
1987-11-30
Budget Start
1986-12-01
Budget End
1987-11-30
Support Year
12
Fiscal Year
1987
Total Cost
Indirect Cost
Name
Mount Sinai School of Medicine
Department
Type
Schools of Medicine
DUNS #
City
New York
State
NY
Country
United States
Zip Code
10029
Perry, D G; Li, S; Hanson, V et al. (1992) Neuromuscular junctions contain NP185: the multifunctional protein is located at the presynaptic site. J Neurosci Res 33:408-17
Puszkin, S; Perry, D; Li, S et al. (1992) Neuronal protein NP185 is developmentally regulated, initially expressed during synaptogenesis, and localized in synaptic terminals. Mol Neurobiol 6:253-83
Perry, D G; Hanson, V; Benuck, M L et al. (1991) Neuronal protein NP185 in avian and murine cerebellum: expression during development and evidence for its presence in nerve endings. J Histochem Cytochem 39:1461-70
Su, B; Hanson, V; Perry, D et al. (1991) Neuronal specific protein NP185 is enriched in nerve endings: binding characteristics for clathrin light chains, synaptic vesicles, and synaptosomal plasma membrane. J Neurosci Res 29:461-73
Silva, W I; Puszkin, S (1990) Equilibrium kinetics model for the cGMP-stimulated phosphodiesterase of brain coated vesicles. Bol Asoc Med P R 82:407-11
Kohtz, D S; Hanson, V; Puszkin, S (1990) Novel proteins mediate an interaction between clathrin-coated vesicles and polymerizing actin filaments. Eur J Biochem 192:291-8
Kohtz, D S; Puszkin, S (1990) Novel NGF-induced proteins in PC12 cells: immunological evidence for their presence in brain nerve endings using a single monoclonal antibody. J Neurosci Res 27:307-13
Kohtz, D S; Puszkin, S (1989) Phosphorylation of tubulin by casein kinase II regulates its binding to a neuronal protein (NP 185) associated with brain coated vesicles. J Neurochem 52:285-95
Puszkin, S; Kohtz, J D; Schook, W J et al. (1989) Clathrin-coated vesicle subtypes in mammalian brain tissue: detection of polypeptide heterogeneity by immunoprecipitation with monoclonal antibodies. J Neurochem 53:51-63
Kohtz, D S; Puszkin, S (1988) A neuronal protein (NP185) associated with clathrin-coated vesicles. Characterization of NP185 with monoclonal antibodies. J Biol Chem 263:7418-25

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