High impact information on COP1

• Similar COP1-binding motifs containing an essential aromatic residue were identified in the cytoplasmic domain of an ER-resident protein, Sec71p, and in an ER retention motif previously characterized in the CD3epsilon chain of the T-cell receptor [1].
• For example, binding of COP1 to dilysine (KKXX) motifs induces specific retrieval of tagged proteins from the Golgi back to the endoplasmic reticulum (ER) [1].
• Extensive mutagenesis of deltaL identified an aromatic residue as a critical determinant of the interaction with COP1 [1].
• In sec28 Delta cells shifted to 37 degrees C, wild-type alpha-COP (Ret1p) levels diminish rapidly and cells accumulate p1 CPY; these defects can be suppressed by alpha-COP overproduction [2].
• Hence, our data provide molecular support for the hypothesis that COP1 is a convergence point for upstream signaling pathways dedicated to individual photoreceptors [3].

Biological context of COP1

• In addition, stably expressed COP1 binds to major vault protein (MVP) and translocated promoter region (Tpr) [4].
• The study of nuclear localization of factors such as COP1 and KN1 is now leading to models for regulating nuclear transport as well as intercellular transport of transcription factors [5].
• Nucleotide sequencing of SOO1 revealed that this gene is identical to the recently reported alpha-COP that is involved in the intracellular protein translocation from endoplasmic reticulum to Golgi and vice versa [6].
• To further investigate SPA1 function in the phyA signaling pathway, we tested whether SPA1, like COP1, mediates changes in gene expression in response to light [3].

Anatomical context of COP1

• Complementation analysis revealed that sec32-1 is an allele of BOS1, a gene implicated in vesicle targeting to the Golgi complex, and sec33-1 is an allele of RET1, a gene that encodes the alpha subunit of coatomer [7].

Associations of COP1 with chemical compounds

• The COP1 protein contains a cysteine-rich zinc-binding RING finger motif found in diverse groups of regulatory proteins [8].

Other interactions of COP1

• Constitutive photomorphogenic 1 (COP1), a protein composed of a RING finger, a coiled-coil domain and seven WD40 repeats, functions as an E3 ubiquitin ligase that targets key transcription factors for ubiquitination and degradation in both higher plants and mammalian cells [4].
• Furthermore we have characterized three new alleles of ret1 and showed that Golgi localization of Emp47p was intact in cells with those mutant alleles [9].

References