Protein Kinases Fpk1p and Fpk2p are Novel Regulators of Phospholipid Asymmetry

• DOI: 10.1091/mbc.e07-07-0646
• Publication Date: 2008-01-17T01:34:09Z
• Authors: Kenzi Nakano; Takaharu Yamamoto; Takuma Kishimoto; Takehiro Noji; Kazuma Tanaka
• Keywords: Protein kinase domain; Flippase

Type 4 P-type ATPases (flippases) are implicated in the generation of phospholipid asymmetry membranes by inward translocation phospholipids. In budding yeast, DRS2/DNF family members Lem3p-Dnf1p/Dnf2p and Cdc50p-Drs2p putative flippases that localized, respectively, to plasma membrane endosomal/trans-Golgi network (TGN) compartments. Herein, we identified a protein kinase gene, FPK1, as mutation exhibited synthetic lethality with cdc50Delta mutation. The domain Fpk1p exhibits high homology plant phototropins fungus Neurospora crassa NRC-2, both which have membrane-associated functions. Simultaneous disruption FPK1 its homolog FPK2 phenocopied lem3Delta/dnf1Delta dnf2Delta mutants, exhibiting impaired NBD-labeled uptake, defects early endosome-to-TGN pathway absence CDC50, hyperpolarized bud growth after exposure phosphatidylethanolamine at tip. fpk1Delta fpk2Delta did not affect subcellular localization Lem3p-Dnf1p or Lem3p-Dnf2p. Further, purified glutathione S-transferase (GST)-fused phosphorylated immunoprecipitated Dnf1p Dnf2p greater extent than Drs2p. We propose Fpk1p/Fpk2p upstream activating kinases for Lem3p-Dnf1p/Dnf2p.