Accession Number : ADA325612

Title :   Presynaptic Calcium Channels: cDNA Cloning.

Descriptive Note : Final rept. 15 Feb 93-14 Feb 97,

Corporate Author : CALIFORNIA UNIV LOS ANGELES DEPT OF PHARMACOLOGY

Personal Author(s) : Gundersen, Cameron B.

PDF Url : ADA325612

Report Date : 01 MAY 1997

Pagination or Media Count : 8

Abstract : This project was aimed at learning more about the role of cysteine string proteins (csps) in the function of presynaptic calcium channels. An unexpected finding that emerged early in the course of this investigation is that csps are synaptic vesicle proteins. Our hypothesis is that csps mediate a novel interaction between synaptic vesicles, and presynaptic calcium channels that only permits these channels to open when there is a vesicle docked in the immediate vicinity of the channel. Studies we conducted using csp mutant Drosophila support this hypothesis. Thus, synaptic transmission is conditionally abolished in these mutants, but this presynaptic block of transmitter release can be overcome by reagents (like, calcium ionophores) that by- pass the calcium channels and allow calcium ions to enter the nerve terminal and trigger secretion. We are now exploring the possibility that this modulatory action of csps is mediated via G-proteins (since we have obtained no evidence of a direct interaction between csps and presynaptic calcium channels), and thereby expect to obtain a better understanding of this interaction at a molecular level.

Descriptors :   *CALCIUM, *MUTATIONS, *CHANNELS, *CYSTEINE, *DROSOPHILA, IONS, MOLECULAR STATES, INTERACTIONS, PROTEINS, RELEASE, TRANSMITTERS, HYPOTHESES, SYNAPSE, LEARNING, NERVES, SECRETION, TRIGGER CIRCUITS.

Subject Categories : Biochemistry
      Microbiology
      Pharmacology

Distribution Statement : APPROVED FOR PUBLIC RELEASE