RACK1 Binds to a Signal Transfer Region of Gβγ and Inhibits Phospholipase C β2 Activation

Songhai Chen,Fang Lin,Heidi E Hamm

doi:10.1074/jbc.m505422200

Songhai Chen, Fang Lin + Show 1 more

Open Access

https://doi.org/10.1074/jbc.m505422200

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Abstract

RACK1 Binds to a Signal Transfer Region of Gβγ and Inhibits Phospholipase C β2 Activation

Highlights

The G␤ subunit has six isoforms, G␤1, G␤2, G␤3, G␤4, and two G␤5 splice variants, long and short [2]
Interaction of Receptor for Activated C Kinase 1 (RACK1) with Different G␤␥ Isoforms—To identify RACK1 binding sites on G␤␥, we first compared the binding of GSTRACK1 to different G␤␥ isoforms, including G␤1␥1, G␤1␥2, and G␤5␥2
Given the similar binding of G␤1␥2 and G␤5␥2 to RACK1, we hypothesized that the RACK1 contact residues on G␤ are localized in these conserved regions

Summary

Introduction

The G␤ subunit has six isoforms, G␤1, G␤2, G␤3, G␤4, and two G␤5 splice variants, long and short [2]. We synthesized a series of peptides corresponding to surface-exposed residues of the conserved regions and determined their effects on the RACK1/G␤␥ interaction (Fig. 2B). Peptides p44 –54 and 328 –337 caused almost complete inhibition of the RACK1/G␤␥ interaction, suggesting that they have additive inhibitory effects (data not shown).

Results

Conclusion