Disease relevance of GPB1

• Because the Gpb1/2 binding domain on Ira1/2 is conserved in the human neurofibromin protein, an analogous signaling network may contribute to the neoplastic development of neurofibromatosis type 1 [1].

High impact information on GPB1

• Here, we define these targets of Gpb1/2 as the yeast neurofibromin homologs Ira1 and Ira2, which function as GTPase activating proteins of Ras [1].
• Our genetic and biochemical studies identify Gpa2 interaction partners (Gpb1/2, Gpg1) and provide evidence that these proteins function as G protein subunit mimics and signaling effectors [2].
• Gpb1 and Gpb2 lack the seven WD-40 repeats found in Gbeta subunits and instead contain seven kelch repeats implicated in protein-protein interactions [2].
• These results suggest that Gpb1 is a negative regulator of conjugation and sporulation that apparently works upstream of Ras1 function in S. pombe [3].
• The G protein beta subunit Gpb1 of Schizosaccharomyces pombe is a negative regulator of sexual development [3].

Biological context of GPB1

• Given that these three enzymes control the synthesis and degradation of cAMP, these results indicate that the effect of Gpb1p and Gpb2p on PKA substrate phosphorylation does not occur by regulating the intracellular cAMP concentration [4].

Physical interactions of GPB1

• In contrast to conventional Galpha subunits, Gpa2 forms an atypical G protein complex with the kelch repeat Gbeta mimic proteins Gpb1 and Gpb2 [5].

Regulatory relationships of GPB1

• Gpb1/2 negatively regulate cAMP signaling by inhibiting Gpa2 and an as yet unidentified target [5].

Other interactions of GPB1

• These findings suggest that Gpb1p and Gpb2p mediate their effects on the cAMP/PKA signaling pathway either by inhibiting the activity of PKA in a cAMP-independent manner or by activating phosphatases that act on PKA substrates [4].

References