title: Intracellular targeting signals and lipid specificity determinants of the ALA/ALIS P4-ATPase complex reside in the catalytic ALA alpha-subunit.
abstract: Members of the P(4) subfamily of P-type ATPases are believed to catalyze flipping of phospholipids across cellular membranes, in this way contributing to vesicle biogenesis in the secretory and endocytic pathways. P(4)-ATPases form heteromeric complexes with Cdc50-like proteins, and it has been suggested that these act as beta-subunits in the P(4)-ATPase transport machinery. In this work, we investigated the role of Cdc50-like beta-subunits of P(4)-ATPases for targeting and function of P(4)-ATPase catalytic alpha-subunits. We show that the Arabidopsis P(4)-ATPases ALA2 and ALA3 gain functionality when coexpressed with any of three different ALIS Cdc50-like beta-subunits. However, the final cellular destination of P(4)-ATPases as well as their lipid substrate specificity are independent of the nature of the ALIS beta-subunit they were allowed to interact with.
authors.affiliation: Center for Membrane Pumps in Cells and Disease, PUMPKIN, Danish National Research Foundation, Department of Plant Biology and Biotechnology, Faculty of Life Sciences, University of Copenhagen, Frederiksberg C, Denmark. rlo@life.ku.dk
authors.forename: Rosa L
authors.initials: RL
authors.lastname: López-Marqués
authors.forename: Lisbeth R
authors.initials: LR
authors.lastname: Poulsen
authors.forename: Susanne
authors.initials: S
authors.lastname: Hanisch
authors.forename: Katharina
authors.initials: K
authors.lastname: Meffert
authors.forename: Morten J
authors.initials: MJ
authors.lastname: Buch-Pedersen
authors.forename: Mia K
authors.initials: MK
authors.lastname: Jakobsen
authors.forename: Thomas Günther
authors.initials: TG
authors.lastname: Pomorski
authors.forename: Michael G
authors.initials: MG
authors.lastname: Palmgren
mesh_terms: D000251:Adenosine Triphosphatases / Q000737:chemistry*; D017360:Arabidopsis / Q000201:enzymology*; D002384:Catalysis; D020134:Catalytic Domain; D002462:Cell Membrane / Q000378:metabolism; D003001:Cloning, Molecular; D005656:Fungal Proteins / Q000737:chemistry; D015723:Gene Library; D008055:Lipids / Q000737:chemistry*; D018613:Microscopy, Confocal / Q000379:methods; D010743:Phospholipids / Q000737:chemistry; D018515:Plant Leaves; D010940:Plant Proteins / Q000737:chemistry*; D017434:Protein Structure, Tertiary; D021122:Protein Subunits / Q000737:chemistry; D013379:Substrate Specificity
chemical_list: D005656:Fungal Proteins; D008055:Lipids; D010743:Phospholipids; D010940:Plant Proteins; D021122:Protein Subunits; D000251:Adenosine Triphosphatases