R.L. López-Marqués, L.R. Poulsen, S. Hanisch, K. Meffert, M.J. Buch-Pedersen, M.K. Jakobsen, T. Günther Pomorski, and M.G. Palmgren (2010).
Intracellular targeting signals and lipid specificity determinants of the ALA/ALIS P4-ATPase complex reside in the catalytic ALA α-subunit.
Molecular Biology of the Cell 21(5): 791–801.
doi: 10.1091/mbc.E09-08-0656

Members of the P4 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. P4-ATPases form heteromeric complexes with Cdc50-like proteins, and it has been suggested that these act as β-subunits in the P4-ATPase transport machinery. In this work, we investigated the role of Cdc50-like β-subunits of P4-ATPases for targeting and function of P4-ATPase catalytic α-subunits. We show that the Arabidopsis P4-ATPases ALA2 and ALA3 gain functionality when coexpressed with any of three different ALIS Cdc50-like β-subunits. However, the final cellular destination of P4-ATPases as well as their lipid substrate specificity are independent of the nature of the ALIS β-subunit they were allowed to interact with.