Journal
PHYSIOLOGICAL GENOMICS
Volume 43, Issue 13, Pages 844-854Publisher
AMER PHYSIOLOGICAL SOC
DOI: 10.1152/physiolgenomics.00002.2011
Keywords
aldosterone pathway; Metazoan evolution
Categories
Funding
- Leducq Foundation
Ask authors/readers for more resources
Despite large changes in salt intake, the mammalian kidney is able to maintain the extracellular sodium concentration and osmolarity within very narrow margins, thereby controlling blood volume and blood pressure. In the aldosterone-sensitive distal nephron (ASDN), aldosterone tightly controls the activities of epithelial sodium channel (ENaC) and Na, K-ATPase, the two limiting factors in establishing transepithelial sodium transport. It has been proposed that the ENaC/degenerin gene family is restricted to Metazoans, whereas the alpha- and beta-subunits of Na, K-ATPase have homologous genes in prokaryotes. This raises the question of the emergence of osmolarity control. By exploring recent genomic data of diverse organisms, we found that: 1) ENaC/degenerin exists in all of the Metazoans screened, including nonbilaterians and, by extension, was already present in ancestors of Metazoa; 2) ENaC/degenerin is also present in Naegleria gruberi, an eukaryotic microbe, consistent with either a vertical inheritance from the last common ancestor of Eukaryotes or a lateral transfer between Naegleria and Metazoan ancestors; and 3) The Na, K-ATPase beta-subunit is restricted to Holozoa, the taxon that includes animals and their closest single-cell relatives. Since the beta-subunit of Na, K-ATPase plays a key role in targeting the alpha-subunit to the plasma membrane and has an additional function in the formation of cell junctions, we propose that the emergence of Na, K-ATPase, together with ENaC/degenerin, is linked to the development of multicellularity in the Metazoan kingdom. The establishment of multicellularity and the associated extracellular compartment (internal milieu) precedes the emergence of other key elements of the aldosterone signaling pathway.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available