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

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.

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.

KW - 14-3-3 Proteins

KW - Amino Acid Sequence

KW - Animals

KW - Carrier Proteins

KW - Cytoplasm

KW - Gene Knockdown Techniques

KW - HEK293 Cells

KW - Humans

KW - Intercellular Signaling Peptides and Proteins

KW - Intracellular Membranes

KW - Isotope Labeling

KW - Mice

KW - Molecular Sequence Data

KW - Mutation

KW - Ouabain

KW - Phosphorylation

KW - Phosphoserine

KW - Protein Binding

KW - Protein Structure, Tertiary

KW - Protein Subunits

KW - Protein Transport

KW - Sodium-Potassium-Exchanging ATPase

KW - Ubiquitin-Conjugating Enzymes

KW - Ubiquitin-Protein Ligases

KW - Ubiquitination

UR - https://www.scopus.com/pages/publications/84872186035

U2 - 10.1242/jcs.110296

DO - 10.1242/jcs.110296

M3 - Article

C2 - 22797923

SN - 0021-9533

VL - 125

SP - 4662

EP - 4675

JO - Journal of Cell Science

JF - Journal of Cell Science

IS - 19

ER -