The plasma membrane (PPM) and the parasitophorous vacuolar membrane (PVM) of Plasmodium fulfill a number of functions that govern the interactions between host and parasite including nutrient transport, transmembrane signal transduction, and membrane traffic between host and parasite membranes. Given the unique growth requirements of intracellular parasites, these membrane processes may be exploitable in developing novel antimalarial drugs. However, little is known concerning the composition and function of these membranes because of difficulties in their isolation. During the past grant period, an immuno-affinity procedure has been developed to purify the PVM. Using this technique and a variation to isolate the PPM, it is proposed: (1) A general physiological characterization of the PPM and PVM in terms of (1) relative solute permeabilities; (b) identification with specific inhibitors transport and ATPase activities of the PVM/PPM; (c) characterize by metabolic labeling and 2-dimensional electrophoresis PVM and PPM proteins as a function of parasite maturation; and (d) PVM lipid bilayer asymmetry and its maintenance by ATP dependent aminophospholipid translocases. (2) An adenine nucleotide translocator identified in either the PVM or PPM is involved in regulating metabolic cooperation between host cell and parasite metabolism. We propose to determine (a) its localization in either the PVM or PPM; (b) its biosynthesis during asexual maturation and gametocytogenesis; (c) regulation of its transport activity; and (d) its gene structure. (3) Detailed analysis of a PPM electrogenic H+-ATPase in terms of (a) regulation by Ca2+, pH, glucose, and cAMP; (b) activity as a function of parasite maturation; (c) biosynthesis and posttranslational modification as investigated by immunological and molecular probes; and (d) using digitized video-intensified fluorescence microscopy, examine the role of the H+-ATPase in regulating intracellular pH and [Ca2+] during parasite development, glucose deprivation and recovery and gametocyte formation.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI024307-05
Application #
3137226
Study Section
Tropical Medicine and Parasitology Study Section (TMP)
Project Start
1988-07-01
Project End
1996-07-31
Budget Start
1992-09-01
Budget End
1993-07-31
Support Year
5
Fiscal Year
1992
Total Cost
Indirect Cost
Name
Virginia Commonwealth University
Department
Type
Schools of Medicine
DUNS #
City
Richmond
State
VA
Country
United States
Zip Code
23298