In plants there are various kinds of P-type ATPases. What is difference between P4-ATPase and P5-ATPase?


1 Answer 1


There are numerous differences between the various subtypes of P-type ATPases, simply because they have different amino acid sequences. Three important differences between P4 and P5 subtypes of P-type ATPases are the following:

  1. Structurally, P4 ATPases have their supporting structural domain (S) in the C-terminus, while P5 ATPases have the S domain divided over the N and C termini. Figure 1 shows the basic structure of P-type ATPases.
  2. Structurally, P4-ATPAses require a beta-subunit for proper function (Poulsen et al., 2008). As the substrate for P5-ATPases is unknown, it could not yet be tested if they also require a beta-subunit.
  3. Functionally, P4-ATPases are putative lipid flippases, while P5-ATPase pumps have so far (per the 2011 report cited) no assigned substrate specificity.

P-type ATPase
Schematic outline of P-type ATPases. Source: Palmgren & Poul Nissen (2011)

- Palmgren & Poul Nissen, Annu Rev Biophys (2011); 40: 243–66
- Poulsen et al., Plant Cell (2008); 20: 658–76


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