Sumary of Ion and lipid transporters specialize for their niche:
- P-type ATPases translocate substrates across the membrane, and they have evolved into different types taking care of specific substrates within a diverse range..
- Now, key structural aspects have been described on how two different types of P-type ATPases — a Ca2+ transporting Ca2+ -ATPase and a lipid transporting P4-ATPase — have adapted to different substrates and physical environments..
- Many bacteria export intracellular calcium using active transporters homologous to the well-described mammalian Ca2+-ATPases such as plasma-membrane Ca2+-ATPase and sarco-endoplasmic reticulum Ca2+-ATPase (PMCA and SERCA, respectively)..
- Crystal structures of Ca2+-ATPase 1 from Listeria monocytogenes (LMCA1) suggest that LMCA1 is pre-organized for dephosphorylation upon Ca2+ release, which can explain the rapid dephosphorylation observed earlier in single-molecule studies..
- The LMCA1 structures provide insight into the evolutionary divergence and conserved features of this important class of ion transporters that also inform us on central mechanisms of mammalian Ca2+ -ATPases and how they can be regulated or affected by pathological conditions..
- In contrast to ion transporters such as LMCA1, the P4-ATPases transport lipids and are known as lipid flippases..
- Importantly, the lipid transport is coupled to the dephosphorylation reaction of the cycle, where for ion transporting P-type ATPases it is mainly coupled to the phosphorylation reaction….