No presynaptic membrane proteins which anchor nerve terminals to the extracellular matrix (ECM) are known. The goal of my proposed research is to identify and characterize some of these proteins involved with anchoring nerve terminals. Such proteins could mediate the well-known trophic interactions between the nerve terminal and basal lamina during nerve regeneration. Of special interest, therefore, will be those proteins that are specific for a subgroup of synapses. We have identified a proteoglycan from elasmobranch electric organ which has some of the characteristics of such an anchoring protein. It is found on the nerve terminal surface restricted to the synaptic region. It is tightly bound to and enriched in an extracellular matrix (ECM) fraction. Intriguingly, this proteoglycan contains an antigenic determinant which is only associated with the electric organ neurons. Finally, synaptic vesicles also contain a transmembrane proteoglycan which shares this antigenic determinant. Thus, synaptic vesicles also might contain this same proteoglycan. From this data we hypothesize that this proteoglycan is presynaptic membrane protein which links the nerve terminal to the ECM. In addition, the synaptic vesicles may act as vehicles for shuttling this molecule to and from the nerve terminal surface. This research proposal has two basic goals: 1) to determine the validity of the above hypothesis; 2) to identify and characterize other presynaptic membrane proteins which anchor the synaptic ECM. To accomplish the first goal several steps are required. We will determine whether the proteoglycan is an integral membrane protein by the presence or absence of a hydrophobic tail. We will identify the ECM components which bind the proteoglycan. If the proteoglycan is an integral membrane protein and binds ECM components, it must link the nerve terminal to the matrix. If this linkage is through the pathway specific antigenic determinant, this linkage could be specific to this synapse. A biochemical comparison of the synaptic vesicle and ECM proteoglycan protein cores will determine whether these two molecules could share a precursor-product relationship. To achieve the second goal we will use the ECM fraction, in which the nerve terminal proteoglycan was originally found. We will isolate a subfraction containing the integral membrane proteins contained in this ECM material. If presynaptic membrane proteins (other than the proteoglycan) bind to the ECM, they should be present in this subfraction. By making monoclonal antibodies against this subfraction, we should be able to identify them.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
2R01NS022367-04
Application #
3404637
Study Section
Neurology B Subcommittee 1 (NEUB)
Project Start
1985-07-01
Project End
1993-06-30
Budget Start
1988-07-01
Budget End
1989-06-30
Support Year
4
Fiscal Year
1988
Total Cost
Indirect Cost
Name
University of Washington
Department
Type
Schools of Medicine
DUNS #
135646524
City
Seattle
State
WA
Country
United States
Zip Code
98195
Sunderland, W J; Son, Y J; Miner, J H et al. (2000) The presynaptic calcium channel is part of a transmembrane complex linking a synaptic laminin (alpha4beta2gamma1) with non-erythroid spectrin. J Neurosci 20:1009-19
Son, Y J; Scranton, T W; Sunderland, W J et al. (2000) The synaptic vesicle protein SV2 is complexed with an alpha5-containing laminin on the nerve terminal surface. J Biol Chem 275:451-60
Russell, A B; Carlson, S S (1997) Neurexin is expressed on nerves, but not at nerve terminals, in the electric organ. J Neurosci 17:4734-43
Walter, J S; Griffith, P; Sweeney, J et al. (1997) Multielectrode nerve cuff stimulation of the median nerve produces selective movements in a raccoon animal model. J Spinal Cord Med 20:233-43
Robinson, C J; Wurster, R D; Walter, J S (1997) Testing peripheral somatosensory neuroprostheses by recording from raccoon cortex. IEEE Trans Rehabil Eng 5:75-80
Carlson, S S; Iwata, M; Wight, T N (1996) A chondroitin sulfate/keratan sulfate proteoglycan, PG-1000, forms complexes which are concentrated in the reticular laminae of electric organ basement membranes. Matrix Biol 15:281-92
Snow, A D; Nochlin, D; Sekiguichi, R et al. (1996) Identification in immunolocalization of a new class of proteoglycan (keratan sulfate) to the neuritic plaques of Alzheimer's disease. Exp Neurol 138:305-17
Walter, J S; Griffith, P; Scarpine, V et al. (1996) The raccoon as an animal model for upper limb neural prosthetics. J Spinal Cord Med 19:234-41
Walter, J S; McLane, J; Cai, W et al. (1995) Evaluation of a thin-film peripheral nerve cuff electrode. J Spinal Cord Med 18:28-32
Iwata, M; Carlson, S S (1993) A large chondroitin sulfate proteoglycan has the characteristics of a general extracellular matrix component of adult brain. J Neurosci 13:195-207

Showing the most recent 10 out of 14 publications