Oligomerization of NHERF-1 and NHERF-2 PDZ domains: differential regulation by association with receptor carboxyl-termini and by phosphorylation

Biochemistry. 2001 Jul 24;40(29):8572-80. doi: 10.1021/bi0103516.


PDZ domains bind to the carboxyl-termini of target proteins, and some PDZ domains are capable of oligomerization to facilitate the formation of intracellular signaling complexes. The Na(+)/H(+) exchanger regulatory factor (NHERF-1; also called "EBP50") and its relative NHERF-2 (also called "E3KARP", "SIP-1", and "TKA-1") both have two PDZ domains. We report here that the PDZ domains of NHERF-1 and NHERF-2 bind specifically to each other but not to other PDZ domains. Purified NHERF-2 PDZ domains associate with each other robustly in the absence of any associated proteins, but purified NHERF-1 PDZ domains associate with each other only weakly when examined alone. The oligomerization of the NHERF-1 PDZ domains is greatly facilitated when they are bound with carboxyl-terminal ligands, such as the carboxyl-termini of the beta(2)-adrenergic receptor or the platelet-derived growth factor receptor. Oligomerization of full-length NHERF-1 is also enhanced by mutation of serine 289 to aspartate (S289D), which mimics the phosphorylated form of NHERF-1. Co-immunoprecipitation experiments with differentially tagged versions of the NHERF proteins reveal that NHERF-1 and NHERF-2 form homo- and hetero-oligomers in a cellular context. A point-mutated version of NHERF-1 (S289A), which cannot be phosphorylated on serine 289, exhibits a reduced capacity for co-immunoprecipitation from cells. These studies reveal that both NHERF-1 and NHERF-2 can oligomerize, which may facilitate NHERF-mediated formation of cellular signaling complexes. These studies furthermore reveal that oligomerization of NHERF-1, but not NHERF-2, is highly regulated by association with other proteins and by phosphorylation.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism*
  • Cell Line
  • Cytoskeletal Proteins / genetics
  • Cytoskeletal Proteins / metabolism*
  • Drosophila Proteins*
  • Humans
  • Insect Proteins / genetics
  • Insect Proteins / metabolism
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism
  • Mutagenesis, Site-Directed
  • Nerve Tissue Proteins / genetics
  • Nerve Tissue Proteins / metabolism
  • Peptide Fragments / genetics
  • Peptide Fragments / metabolism*
  • Phosphoproteins / genetics
  • Phosphoproteins / metabolism*
  • Phosphorylation
  • Protein Structure, Tertiary / genetics
  • Rabbits
  • Receptors, Platelet-Derived Growth Factor / genetics
  • Receptors, Platelet-Derived Growth Factor / metabolism*
  • Recombinant Fusion Proteins / metabolism
  • Sequence Homology, Amino Acid*
  • Serine / genetics
  • Sodium-Hydrogen Exchangers / genetics
  • Sodium-Hydrogen Exchangers / metabolism*
  • Transfection
  • Zonula Occludens-1 Protein


  • Carrier Proteins
  • Cytoskeletal Proteins
  • Drosophila Proteins
  • Insect Proteins
  • Membrane Proteins
  • Nerve Tissue Proteins
  • Peptide Fragments
  • Phosphoproteins
  • Recombinant Fusion Proteins
  • SLC9A2 protein, human
  • Sodium-Hydrogen Exchangers
  • TJP1 protein, human
  • Zonula Occludens-1 Protein
  • dlt protein, Drosophila
  • postsynaptic density proteins
  • sodium-hydrogen exchanger regulatory factor
  • Serine
  • Receptors, Platelet-Derived Growth Factor