Open Access

EHDS are serine phosphoproteins: EHD1 phosphorylation is enhanced by serum stimulation

  • Boris Fichtman1,
  • Liat Ravid2,
  • Debora Rapaport3 and
  • Mia Horowitz3Email author
Cellular & Molecular Biology LettersAn International Journal200813:27

DOI: 10.2478/s11658-008-0027-4

Received: 21 February 2008

Accepted: 6 May 2008

Published: 25 July 2008

Abstract

Endocytic processes are mediated by multiple protein-protein interacting modules and regulated by phosphorylation and dephosphorylation. The Eps15 homology domain containing protein 1 (EHD1) has been implicated in regulating recycling of proteins, internalized both in clathrin-dependent and clathrin-independent endocytic pathways, from the recycling compartment to the plasma membrane. EHD1 was found in a complex with clathrin, adaptor protein complex-2 (AP-2) and insulin-like growth factor-1 receptor (IGF-1R), and was shown to interact with Rabenosyn-5, SNAP29, EHBP1 (EH domain binding protein 1) and syndapin I and II. In this study, we show that EHD1, like the other human EHDs, undergoes serine-phosphorylation. Our results also indicate that EHD1 is a serum-inducible serine-phosphoprotein and that PKC (protein kinase C) is one of its kinases. In addition, we show that inhibitors of clathrin-mediated endocytosis decrease EHD1 phosphorylation, while inhibitors of caveolinmediated endocytosis do not affect EHD1 phosphorylation. The results of experiments in which inhibitors of endocytosis were employed strongly suggest that EHD1 phosphorylation occurs between early endosomes and the endocytic recycling compartment.

Key words

Endocytosis EHD1 EH domain Phosphorylation

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