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A major transmembrane protein of Golgi-derived COPI-coated vesicles involved in coatomer binding

K Sohn1, L Orci, M Ravazzola

  • 1Institut für Biochemie I, Universität Heidelberg, Germany.

The Journal of Cell Biology
|December 1, 1996
PubMed

Insights

Researchers identified p23, a Golgi-specific protein, as a key receptor for coatomer. This protein is crucial for the formation of COPI-coated vesicles during intracellular transport.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Biochemistry

Background:

  • Non-clathrin-coated vesicle formation at the Golgi requires cytosolic factors.
  • Identifying key membrane proteins is essential for understanding vesicle budding.

Purpose of the Study:

  • To identify membrane proteins involved in non-clathrin-coated vesicle budding.
  • To characterize the role of a specific type I transmembrane protein, p23, in this process.

Main Methods:

  • Isolation and cDNA cloning of p23 from mammalian Golgi-derived COPI-coated vesicles.
  • Sequence analysis of the p23 cytoplasmic tail and comparison with known retrieval motifs.
  • Biochemical analysis of p23 localization and enrichment during vesicle formation.

Main Results:

  • p23 belongs to the p24 family and possesses a unique cytoplasmic tail.
  • The p23 tail binds coatomer, similar to KKXX motifs, but with an additional binding element.
  • p23 is specifically localized to Golgi cisternae and concentrates in COPI-coated buds and vesicles.
  • p23 is significantly enriched in vesicles and present stoichiometrically with ARF and coatomer.

Conclusions:

  • p23 acts as a Golgi-specific receptor for coatomer.
  • p23 plays a vital role in the formation of COPI-coated vesicles.

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