The alpha- and beta'-COP WD40 domains mediate cargo-selective interactions with distinct di-lysine motifs.

Coatomer is required for the retrieval of proteins from an early Golgi compartment back to the endoplasmic reticulum. The WD40 domain of alpha-COP is required for the recruitment of KKTN-tagged proteins into coatomer-coated vesicles. However, lack of the domain has only minor effects on growth in yeast. Here, we show ...
that the WD40 domain of beta'-COP is required for the recycling of the KTKLL-tagged Golgi protein Emp47p. The protein is degraded more rapidly in cells with a point mutation in the WD40 domain of beta'-COP (sec27-95) or in cells lacking the domain altogether, whereas a point mutation in the Clathrin Heavy Chain Repeat (sec27-1) does not affect the turnover of Emp47p. Lack of the WD40 domain of beta'-COP has only minor effects on growth of yeast cells; however, absence of both WD40 domains of alpha- and beta'-COP is lethal. Two hybrid studies together with our analysis of the maturation of KKTN-tagged invertase and the turnover of Emp47p in alpha- and beta'-COP mutants suggest that the two WD40 domains of alpha- and beta'-COP bind distinct but overlapping sets of di-lysine signals and hence both contribute to recycling of proteins with di-lysine signals.
Mesh Terms:
COP-Coated Vesicles, Coatomer Protein, Endoplasmic Reticulum, Golgi Apparatus, Lysine, Membrane Proteins, Mutation, Protein Binding, Protein Structure, Tertiary, Protein Transport, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins, Two-Hybrid System Techniques, Vesicular Transport Proteins
Mol. Biol. Cell
Date: Mar. 01, 2004
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