Transcriptional activator required for the expression of glycolytic and ribosomal genes. Forms a transcriptional activation complex with RAP1, RAP1 providing the specific DNA-binding function and GCR1 providing the activation function. Can also bind itself to DNA to a core 5'-CTTCC-3' sequence (CT box). CT box-binding is not essential, but enhances the activation function of the RAP1-GCR1 complex in promoters that contain both DNA signals (only glycolytic genes). CT box-dependent transcriptional activation requires GCR2. Homodimer via the leucine-zipper domain. Forms a complex with a GCR2 homodimer. Interacts with RAP1. Phosphorylated in a GCR2-dependent manner. Present with 259 molecules/cell in log phase SD medium.