High impact information on REG1

• In contrast, expression of LexA-Reg1p containing mutations at phenylalanine in the putative PP-1C-binding site motif (K/R)(X)(I/V)XF was unable to rescue Hxk2p dephosphorylation in intact yeast or restore Hxk2p phosphatase activity [1].
• Protein phosphatase 1 (Glc7p) and its binding protein Reg1p are essential for the regulation of glucose repression pathways in Saccharomyces cerevisiae [1].
• Consistent with increased phosphorylation of Hxk2p in response to REG1 deletion, fractionation of yeast extracts by anion-exchange chromatography identified Hxk2p phosphatase activity in wild-type strains that was selectively lost in the reg1Delta mutant [1].
• Here we show that Reg1 interacts with the Snf1 catalytic domain in the two-hybrid system [2].
• In Saccharomyces cerevisiae, the protein phosphatase type 1 (PP1)-binding protein Reg1 is required to maintain complete repression of ADH2 expression during growth on glucose [3].

Biological context of REG1

• Mutants with a deletion of reg1 display a mild slow-growth defect, while reg2 mutants exhibit a wild-type phenotype [4].
• The HEX2 gene encodes a protein of 114137 Da, deduced from its DNA sequence [5].
• Deletion of REG1 in a wild-type background led to overaccumulation of glycogen as well as slow growth and an enlarged cell size [6].
• The REG1 gene encodes a regulatory subunit of the type-1 protein phosphatase (PP1) G1c7 in Saccharomyces cerevisiae, which directs the catalytic subunit to substrates involved in glucose repression [7].
• These lesions proved to be in the same gene, SRN1, identified previously in a search for second-site suppressors of mutations that affect the removal of intervening sequences from pre-mRNAs [8].

Anatomical context of REG1

• The glc7-T152K mutant strain exhibited a reduced Reg1p binding along with defects in FBPase degradation and Vid vesicle trafficking to the vacuole [9].

Associations of REG1 with chemical compounds

• These results indicate that REG1 has a unique role in the glucose repression pathway but acts together with REG2 to regulate some as yet uncharacterized function important for growth [4].
• This indicates that REG1 can act independently of phosphorylation at serine 230 [10].
• The REG1 gene product is required for repression of INO1 and other inositol-sensitive upstream activating sequence-containing genes of yeast [11].
• The hex2 mutants have pleiotropic defects in the regulation of glucose-repressible enzymes, hexokinase PII synthesis and maltose uptake [Entian, K.-D. & Zimmermann, F.K. (1980) Mol. Gen. Genet. 177, 345-350] [5].
• Cells lacking the Reg1 protein, a regulatory subunit for the Glc7 phosphatase, showed constitutive phosphorylation of Snf1 threonine 210 [12].

Physical interactions of REG1

• Functional analysis of the yeast Glc7-binding protein Reg1 identifies a protein phosphatase type 1-binding motif as essential for repression of ADH2 expression [3].

Enzymatic interactions of REG1

• Mutants of gene HEX1 had a reduced hexose phosphorylating activity on all media whereas those of gene HEX2 had elevated levels but only in glucose grown cells [13].

Other interactions of REG1

• The phosphorylation state of Hxk2p and Hxk2p phosphatase activity was restored to wild-type levels in the reg1Delta mutant by expression of a LexA-Reg1p fusion protein [1].
• Overexpression of HEX2 resulted in a 70% reduction of GAL1 expression under induced growth conditions [5].
• In order to identify physiological substrates for the Glc7p-Reg1p complex, we examined the effects of deletion of the REG1 gene on the yeast phosphoproteome [1].
• Protein phosphatase type-1 regulatory subunits Reg1p and Reg2p act as signal transducers in the glucose-induced inactivation of maltose permease in Saccharomyces cerevisiae [7].
• Interestingly, SRN1 is not a negative regulator of RNA1 at the transcriptional, translational, or protein stability level [8].

Analytical, diagnostic and therapeutic context of REG1

• Flow cytometry measurements showed that G1 arrest of the hex2 mutant under such conditions was incomplete [14].

References