title: Products of the grg (Groucho-related gene) family can dimerize through the amino-terminal Q domain.
abstract: The murine grg (Groucho-related gene) products are believed to interact with transcription factors and repress transcription, thereby regulating cell proliferation and differentiation. Most proteins in the grg family contain all of the domains found in the Drosophila Groucho protein, including the S/P (Ser-Pro-rich) domain required for interaction with transcription factors and the WD40 domain, which is thought to interact with other proteins. However, at least two Grg proteins contain only the amino-terminal Q (glutamine-rich) domain. We examined whether the Q domain is used for dimerization between Grg proteins, using the yeast two-hybrid system and binding assays with glutathione S-transferase fusion proteins. We found that Grg proteins are able to dimerize through the Q domain and that dimerization requires a core of 50 amino acids. Surprisingly, the dimerization does not require the leucine zipper located within the Q domain.
authors.affiliation: Molecular Biology Institute, Cancer Research Group and Departments of Biochemistry and Medical Sciences, McMaster University, Hamilton, Ontario L8S 4K1, Canada.
authors.forename: M
authors.initials: M
authors.lastname: Pinto
authors.forename: C G
authors.initials: CG
authors.lastname: Lobe
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D056970:Co-Repressor Proteins; D005973:Glutamine; D016350:Leucine Zippers; D051379:Mice; D008969:Molecular Sequence Data; D008970:Molecular Weight; D016297:Mutagenesis, Site-Directed; D011485:Protein Binding; D011506:Proteins / Q000737:chemistry*; D011994:Recombinant Proteins; D013329:Structure-Activity Relationship; D014157:Transcription Factors / Q000378:metabolism
chemical_list: D056970:Co-Repressor Proteins; D011506:Proteins; D011994:Recombinant Proteins; C089462:Tle5 protein, mouse; D014157:Transcription Factors; D005973:Glutamine