ZNRF2 is released from membranes by growth factors and with ZNRF1 regulates the Na+/K+ATPase

TY - JOUR

T1 - ZNRF2 is released from membranes by growth factors and with ZNRF1 regulates the Na+/K+ATPase

A1 - Hoxhaj,Gerta

A1 - Najafov,Ayaz

A1 - Toth,Rachel

A1 - Campbell,David G.

A1 - Prescott,Alan R.

A1 - MacKintosh,Carol

AU - Hoxhaj,Gerta

AU - Najafov,Ayaz

AU - Toth,Rachel

AU - Campbell,David G.

AU - Prescott,Alan R.

AU - MacKintosh,Carol

PY - 2012/10/1

Y1 - 2012/10/1

N2 - Here, we describe a phosphorylation-based reverse myristoyl switch for mammalian ZNRF2, and show that this E3 ubiquitin ligase and its sister protein ZNRF1 regulate the Na+/K+ pump (Na+/K+ATPase). N-myristoylation localizes ZNRF1 and ZNRF2 to intracellular membranes and enhances their activity. However, when ZNRF2 is phosphorylated in response to agonists including insulin and growth factors, it binds to 14-3-3 and is released into the cytosol. On membranes, ZNRF1 and ZNRF2 interact with the Na+/K+ATPase a1 subunit via their UBZ domains, while their RING domains interact with E2 proteins, predominantly Ubc13 that, together with Uev1a, mediates formation of Lys63-ubiquitin linkages. ZNRF1 and ZNRF2 can ubiquitylate the cytoplasmic loop encompassing the nucleotide-binding and phosphorylation regions of the Na+/K+ATPase a1 subunit. Ouabain, a Na+/K+ATPase inhibitor and therapeutic cardiac glycoside, decreases ZNRF1 protein levels, whereas knockdown of ZNRF2 inhibits the ouabain-induced decrease of cell surface and total Na+/K+ATPase a1 levels. Thus, ZNRF1 and ZNRF2 are new players in regulation of the ubiquitous Na+/K+ATPase that is tuned to changing demands in many physiological contexts. <br/><br/>

AB - Here, we describe a phosphorylation-based reverse myristoyl switch for mammalian ZNRF2, and show that this E3 ubiquitin ligase and its sister protein ZNRF1 regulate the Na+/K+ pump (Na+/K+ATPase). N-myristoylation localizes ZNRF1 and ZNRF2 to intracellular membranes and enhances their activity. However, when ZNRF2 is phosphorylated in response to agonists including insulin and growth factors, it binds to 14-3-3 and is released into the cytosol. On membranes, ZNRF1 and ZNRF2 interact with the Na+/K+ATPase a1 subunit via their UBZ domains, while their RING domains interact with E2 proteins, predominantly Ubc13 that, together with Uev1a, mediates formation of Lys63-ubiquitin linkages. ZNRF1 and ZNRF2 can ubiquitylate the cytoplasmic loop encompassing the nucleotide-binding and phosphorylation regions of the Na+/K+ATPase a1 subunit. Ouabain, a Na+/K+ATPase inhibitor and therapeutic cardiac glycoside, decreases ZNRF1 protein levels, whereas knockdown of ZNRF2 inhibits the ouabain-induced decrease of cell surface and total Na+/K+ATPase a1 levels. Thus, ZNRF1 and ZNRF2 are new players in regulation of the ubiquitous Na+/K+ATPase that is tuned to changing demands in many physiological contexts. <br/><br/>

KW - Myristoyl switch

KW - Protein trafficking

KW - Ubiquitylation

KW - Na+/K+ATPase

KW - Na+ pump

KW - Sodium pump

U2 - 10.1242/jcs.110296

DO - 10.1242/jcs.110296

M1 - Article

JO - Journal of Cell Science

JF - Journal of Cell Science

SN - 0021-9533

IS - 19

VL - 125

SP - 4662

EP - 4675

ER -