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.
Eugster
Anne
A
Department of Clinical Biochemistry, Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 2XY, United Kingdom.
Frigerio
Gabriella
G
Dale
Martin
M
Duden
Rainer
R
D022181:COP-Coated Vesicles / Q000235:genetics / Q000378:metabolism; D020756:Coatomer Protein / Q000235:genetics / Q000378:metabolism*; D004721:Endoplasmic Reticulum / Q000235:genetics / Q000378:metabolism*; D006056:Golgi Apparatus / Q000235:genetics / Q000378:metabolism*; D008239:Lysine / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D011485:Protein Binding; D017434:Protein Structure, Tertiary / Q000235:genetics; D021381:Protein Transport / Q000235:genetics / Q000502:physiology; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D020798:Two-Hybrid System Techniques; D033921:Vesicular Transport Proteins
D020756:Coatomer Protein; C096914:EMP47 protein, S cerevisiae; D008565:Membrane Proteins; D029701:Saccharomyces cerevisiae Proteins; D033921:Vesicular Transport Proteins; D008239:Lysine