Phosphorylation-induced Conformational Changes in Rap1b

Edreira, Martín M.; Li, Sheng; Hochbaum, Daniel; Wong, Sergio E.; Gorfe, Alemayehu A.; Ribeiro-Neto, Fernando; Woods, Virgil L.; Altschuler, Daniel L.

doi:10.1074/jbc.m109.011312

Cited by 44 publications

(18 citation statements)

References 37 publications

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“…These striking changes in GTP-bound-K-Ras dynamics enable its GTPase activity. Note that this nucleotide exchange is the first step in active to inactive transition5556575859606162. Overall, our results support the well-established allosteric nature of K-Ras activation59, which has been suggested to play an important role in GTPase activity63.…”

Section: Discussionsupporting

confidence: 85%

Intrinsic K-Ras dynamics: A novel molecular dynamics data analysis method shows causality between residue pair motions

Gümüş

Erman

2016

Sci Rep

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K-Ras is the most frequently mutated oncogene in human cancers, but there are still no drugs that directly target it in the clinic. Recent studies utilizing dynamics information show promising results for selectively targeting mutant K-Ras. However, despite extensive characterization, the mechanisms by which K-Ras residue fluctuations transfer allosteric regulatory information remain unknown. Understanding the direction of information flow can provide new mechanistic insights for K-Ras targeting. Here, we present a novel approach –conditional time-delayed correlations (CTC) – using the motions of all residue pairs of a protein to predict directionality in the allosteric regulation of the protein fluctuations. Analyzing nucleotide-dependent intrinsic K-Ras motions with the new approach yields predictions that agree with the literature, showing that GTP-binding stabilizes K-Ras motions and leads to residue correlations with relatively long characteristic decay times. Furthermore, our study is the first to identify driver-follower relationships in correlated motions of K-Ras residue pairs, revealing the direction of information flow during allosteric modulation of its nucleotide-dependent intrinsic activity: active K-Ras Switch-II region motions drive Switch-I region motions, while α-helix-3L7 motions control both. Our results provide novel insights for strategies that directly target mutant K-Ras.

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Section: Discussionsupporting

confidence: 85%

Intrinsic K-Ras dynamics: A novel molecular dynamics data analysis method shows causality between residue pair motions

Gümüş

Erman

2016

Sci Rep

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“…Moreover, the negative effect of forskolin on the GST-Rap1-CAP1 interaction is lost in phosphodeficient GST-Rap1-S179A and fully mimicked by GST-Rap1-S179D ( Fig. 5C) whose phosphomimetic properties were thoroughly characterized in our laboratory (60). These results indicate that forskolin/PKA-mediated Rap1 Ser 179 phosphorylation negatively modulates its interaction with CAP1 in cells.…”

Section: Rap1 Ser 179 Phosphorylation Does Not Directly Affect Bindinmentioning

confidence: 54%

Cyclase-associated protein 1 (CAP1) is a prenyl-binding partner of Rap1 GTPase

Zhang

Cao

Barila

et al. 2018

Journal of Biological Chemistry

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Rap1 proteins are members of the Ras subfamily of small GTPases involved in many biological responses, including adhesion, cell proliferation, and differentiation. Like all small GTPases, they work as molecular allosteric units that are active in signaling only when associated with the proper membrane compartment. Prenylation, occurring in the cytosol, is an enzymatic posttranslational event that anchors small GTPases at the membrane, and prenyl-binding proteins are needed to mask the cytoplasm-exposed lipid during transit to the target membrane. However, several of these proteins still await discovery. In this study, we report that cyclase-associated protein 1 (CAP1) binds Rap1. We found that this binding is GTP-independent, does not involve Rap1's effector domain, and is fully contained in its C-terminal hypervariable region (HVR). Furthermore, Rap1 prenylation was required for high-affinity interactions with CAP1 in a geranylgeranyl-specific manner. The prenyl binding specifically involved CAP1's C-terminal hydrophobic β-sheet domain. We present a combination of experimental and computational approaches, yielding a model whereby the high-affinity binding between Rap1 and CAP1 involves electrostatic and nonpolar side-chain interactions between Rap1's HVR residues, lipid, and CAP1 β-sheet domain. The binding was stabilized by the lipid insertion into the β-solenoid whose interior was occupied by nonpolar side chains. This model was reminiscent of the recently solved structure of the PDEδ-K-Ras complex; accordingly, disruptors of this complex, deltarasin, blocked the Rap1-CAP1 interaction. These findings indicate that CAP1 is a geranylgeranyl-binding partner of Rap1.

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“…However, in our hands, Rap1 protein levels were not altered by phosphorylation. Other studies have proposed that phosphorylation of Rap1 regulates the level of interaction of effectors with GTP-loaded (activated) Rap1 (50,51). However, when we examine binding of RapL to GTP-loaded Rap1, we see no additional effect of phosphorylation at Ser-180.…”

Section: Discussionmentioning

confidence: 56%

Protein Kinase A-dependent Phosphorylation of Rap1 Regulates Its Membrane Localization and Cell Migration

Takahashi

Dillon

Liu

et al. 2013

Journal of Biological Chemistry

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Background:The small G protein Rap1 is phosphorylated within its carboxyl terminus by the cAMP-dependent protein kinase PKA. Results: This phosphorylation removes Rap1 from the plasma membrane to limit Rap1 signaling. Conclusion: Rap1 phosphorylation switches Rap1 off the membrane and terminates its activation. Significance: Carboxyl-terminal phosphorylation may be common among small G proteins to regulate GTP/GDP cycling and downstream signaling.

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Phosphorylation-induced Conformational Changes in Rap1b

Cited by 44 publications

References 37 publications

Intrinsic K-Ras dynamics: A novel molecular dynamics data analysis method shows causality between residue pair motions

Intrinsic K-Ras dynamics: A novel molecular dynamics data analysis method shows causality between residue pair motions

Cyclase-associated protein 1 (CAP1) is a prenyl-binding partner of Rap1 GTPase

Protein Kinase A-dependent Phosphorylation of Rap1 Regulates Its Membrane Localization and Cell Migration

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