Association of protein-tyrosine phosphatase MEG2 via its Sec14p homology domain with vesicle-trafficking proteins

J Biol Chem. 2007 May 18;282(20):15170-8. doi: 10.1074/jbc.M608682200. Epub 2007 Mar 26.

Abstract

The protein-tyrosine phosphatase PTPMEG2 is located on the cytoplasmic face of the enclosing membrane of secretory vesicles, where it regulates vesicle size by promoting homotypic vesicle fusion by dephosphorylating N-ethylmaleimide-sensitive factor, a key regulator of vesicle fusion. Here we address the question of how PTPMEG2 is targeted to this subcellular location. Using a series of deletion mutants, we pinpointed the N-terminal Sec14p homology (SEC14) domain of PTPMEG2, residues 1-261, as the region containing the secretory vesicle targeting signal. This domain, alone or appended to a heterologous protein, was localized to intracellular vesicle membranes. Yeast two-hybrid screening identified a number of secretory vesicle proteins that interacted directly with the SEC14 domain of PTPMEG2, providing a mechanism for PTPMEG2 targeting to secretory vesicles. Two such proteins, mannose 6-phosphate receptor-interacting protein TIP47 and Arfaptin2, were found to alter PTPMEG2 localization when overexpressed, and elimination of TIP47 resulted in loss of PTPMEG2 function. We conclude that the N terminus of PTPMEG2 is necessary for the targeting of this phosphatase to the secretory vesicle compartment by association with other proteins involved in intracellular transport.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adaptor Proteins, Signal Transducing / genetics
  • Adaptor Proteins, Signal Transducing / metabolism*
  • Amino Acid Sequence
  • Biological Transport, Active / physiology
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism*
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism*
  • HeLa Cells
  • Humans
  • Intracellular Signaling Peptides and Proteins / genetics
  • Intracellular Signaling Peptides and Proteins / metabolism*
  • Perilipin-3
  • Pregnancy Proteins / genetics
  • Pregnancy Proteins / metabolism*
  • Protein Structure, Tertiary / genetics
  • Protein Tyrosine Phosphatases / genetics
  • Protein Tyrosine Phosphatases / metabolism*
  • Protein Tyrosine Phosphatases, Non-Receptor
  • R-SNARE Proteins / genetics
  • R-SNARE Proteins / metabolism*
  • Secretory Vesicles / genetics
  • Secretory Vesicles / metabolism*
  • Sequence Deletion
  • Sequence Homology, Amino Acid
  • Vesicular Transport Proteins

Substances

  • ARFIP2 protein, human
  • Adaptor Proteins, Signal Transducing
  • Carrier Proteins
  • DNA-Binding Proteins
  • Intracellular Signaling Peptides and Proteins
  • PLIN3 protein, human
  • Perilipin-3
  • Pregnancy Proteins
  • R-SNARE Proteins
  • Vesicular Transport Proteins
  • PTPN9 protein, human
  • Protein Tyrosine Phosphatases
  • Protein Tyrosine Phosphatases, Non-Receptor