Identification of novel cellular partners involved in controlling reversible dissociation of V-ATPases in vivo

• Applicant: Dr. Regina Saum
• Subject Area: Metabolism, Biochemistry and Genetics of Microorganisms
• Term: from 2009 to 2011
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 152700297

Eukaryotic cells have evolved a family of ATP-dependent proton pumps known as the vacuolar H+-ATPases (V-ATPases). V-ATPases are present in a variety of intracellular compartments where they are responsible for pH homeostasis by pumping protons across the membrane at the expense of ATP. Acidification of organelles is essential in membrane trafficking, protein degradation, coupled transport of small molecules, and the entry of various pathogens. Furthermore, V-ATPases play a crucial role for normal physiological processes as well as in a number of human diseases. A rapid and effective mechanism for regulating the activity of V-ATPases involves dissociation and association of the two functional domains, V1 and VO. To date, this process is best characterized in yeast, where V-ATPases are reversibly disassembled in response to glucose depletion. Although the Ras/cAMP/PKA (protein kinase A) pathway has recently been shown to function in regulation of reversible dissociation of the V-ATPase in yeast, nothing is known about the proteins that connect PKA to this process. It is also not known whether subunits of the V-ATPase or associated proteins are substrates of PKA. This proposal will search for novel proteins downstream of PKA that are involved in reversible dissociation using a novel genetic screen that identifies mutants defective in this process. Experiments will also be performed to test whether V-ATPase subunits or proteins associated with the complex become phosphorylated or dephosphorylated during reversible dissociation.

• DFG Programme: Research Fellowships
• International Connection: USA
• Host: Professor Dr. Michael Forgac