Toxicoproteomic Study of the Disruption of
the Neuronal SNARE Complex by the Presence of Lead, Cadmium,
Manganese and Nickel
Velda E. Glover, St. John’s
University Student
Marc E. Gillespie, Department of
Pharmaceutical Sciences, College of Pharmacy and Allied Health
Professions,
Abstract: The nervous system is a
critical target for heavy metal toxicity. The neuronal SNARE
proteins (SNAP 25, VAMP 2 and Syntaxin 1A) are critical for vesicle
fusion and their membrane fusing properties are regulated by
calcium, making these proteins particularly susceptible to
misregulation by heavy metals. In my project a number of metals are
used to potentially disrupt the functions of the SNARE complex.
Complexes containing neuronal SNARE SNAP25b and gene products from
a neuronal human brain cDNA library are screened using a modified
yeast two-hybrid system. This methodology is used to detect
protein-protein interactions that are disrupted by exogenous
toxicants. Four concentrations of each metal were used in addition
to controls. The results of three transformations were pooled. Out
of one hundred and fifty four transformants, thirty potential
interactors were analyzed in the toxicology screen. A colorimetric
assay was performed to quantify ?-galatosidase activity. On cadmium
plates, five colonies showed disrupted complexes (light blue) as
compared to controls (dark blue). For manganese, seven colonies
showed disrupted complexes as compared to control. Nickel acted as
a microbial and the yeast did not survive the screen at the two
highest concentrations. As seen previously in our lab, lead had no
toxic effect. Identification of strains containing SNAP25b and
novel protein partners disrupted by various heavy metals will lead
to a body of data that will be used to discover potential
biomarkers of metal toxicity.
Identification and Evaluation of Chronic Low-Level Pb Toxicity
Biomarkers in Neonatal Rats