Ping Wang, M.S., 2001-2003

B.S. in Microbiology at Northwest Univ. in Xi'an, China, 1992

Ping isolated and characterized (with Sudipta Saraswati in the lab) a novel paralytic mutant, nubian, in a behavioral screen for conditional temperature-sensitive seizure mutants in Drosophila melanogaster.  nubian mutants display reduced lifespan, abnormal motor behavior, altered synaptic structure and defective neurotransmitter release.  The nubian mutant disrupts phosphoglycerate kinase (PGK), an enzyme required for ATP generation in the terminal stage of the glycolytic pathway.  Consistent with altered ATP generation in nubian animals, brain extracts show a 3-fold reduction in resting ATP levels compared to controls.  Microarray analysis of nubian mutants reveals altered transcription of genes implicated in glucose and lipid metabolism.  Disruption of ATP generation in nubian animals is accompanied by temperature-dependent defects in neuronal activity, with initial seizure activity, followed by an activity-dependent loss of synaptic transmission.  nubian mutants also display structural defects at the synapse, with larger varicosity size but normal varicosity number, indicating these synaptic parameters are independently regulated.  Both exocytotic (NSF) and endocytotic (dynamin) ATPase/GTPase activity is required for normal synaptic transmission.  Biochemical and physiological analyses indicate synaptic defects in nubian animals are secondary to defective endocytosis, suggesting endocytotic pathways may be generally more sensitive to altered ATP levels than those used for exocytosis.  Alterations in ATP metabolism likely disrupt similar pathways in humans, as PGK deficiency is associated with mental retardation, seizures and exercise intolerance.  Given the behavioral similarities between disruptions of PGK function in Drosophila and humans, the analysis of nubian animals may reveal conserved neuronal responses associated with altered ATP generation within the brain.