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Structural insight into mechanisms for dynamic regulation of PKM2.

Wang P, Sun C, Zhu T, Xu Y - Protein Cell (2015)

Bottom Line: We determined crystal structures of human PKM2 mutants and proposed a "seesaw" model to illustrate conformational changes between an inactive T-state and an active R-state tetramers of PKM2.K422R, a patient-derived mutation of PKM2, favors a stable, inactive T-state tetramer because of strong intermolecular interactions.Our study reveals the mechanism for dynamic regulation of PKM2 by post-translational modifications and a patient-derived mutation and provides a structural basis for further investigation of other modifications and mutations of PKM2 yet to be discovered.

View Article: PubMed Central - PubMed

Affiliation: Fudan University Shanghai Cancer Center and Institute of Biomedical Sciences, Shanghai Medical College of Fudan University, Shanghai, 200032, China.

ABSTRACT
Pyruvate kinase isoform M2 (PKM2) converts phosphoenolpyruvate (PEP) to pyruvate and plays an important role in cancer metabolism. Here, we show that post-translational modifications and a patient-derived mutation regulate pyruvate kinase activity of PKM2 through modulating the conformation of the PKM2 tetramer. We determined crystal structures of human PKM2 mutants and proposed a "seesaw" model to illustrate conformational changes between an inactive T-state and an active R-state tetramers of PKM2. Biochemical and structural analyses demonstrate that PKM2(Y105E) (phosphorylation mimic of Y105) decreases pyruvate kinase activity by inhibiting FBP (fructose 1,6-bisphosphate)-induced R-state formation, and PKM2(K305Q) (acetylation mimic of K305) abolishes the activity by hindering tetramer formation. K422R, a patient-derived mutation of PKM2, favors a stable, inactive T-state tetramer because of strong intermolecular interactions. Our study reveals the mechanism for dynamic regulation of PKM2 by post-translational modifications and a patient-derived mutation and provides a structural basis for further investigation of other modifications and mutations of PKM2 yet to be discovered.

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Crystal structure of human PKM2 and a “seesaw” model for conformational transitions of PKM2 tetramer. (A) Ribbon representation of the human PKM2 structure (PKM2K422R) with A-A′ (red box) and C-C′ (yellow box) interfaces indicated as dashed lines. Four monomers are shown in different colors. (B and C) A “seesaw” model for the conformational transitions between the R-state (B) and T-state (C) conformations of the PKM2 tetramer. Critical elements for the conformational changes are indicated. Dashed arrows indicate the directions for the rotation of each monomer from the R- (B) to the T- (C) state. The monomers are indicated as monomer A to D for simplicity in the following description. (D and E) A close-up view for the structural comparison of the PKM2 structure in the R- and T-state conformations on the C-C′ (D) or A-A′ (E) interface. PKM2 in R- and T-state conformations are colored in yellow and blue, respectively. (F) A structural comparison of the active site of PKM2 in R- and T-state tetramers. PKM2 in R- and T-state conformations are colored in yellow and blue, respectively
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Fig2: Crystal structure of human PKM2 and a “seesaw” model for conformational transitions of PKM2 tetramer. (A) Ribbon representation of the human PKM2 structure (PKM2K422R) with A-A′ (red box) and C-C′ (yellow box) interfaces indicated as dashed lines. Four monomers are shown in different colors. (B and C) A “seesaw” model for the conformational transitions between the R-state (B) and T-state (C) conformations of the PKM2 tetramer. Critical elements for the conformational changes are indicated. Dashed arrows indicate the directions for the rotation of each monomer from the R- (B) to the T- (C) state. The monomers are indicated as monomer A to D for simplicity in the following description. (D and E) A close-up view for the structural comparison of the PKM2 structure in the R- and T-state conformations on the C-C′ (D) or A-A′ (E) interface. PKM2 in R- and T-state conformations are colored in yellow and blue, respectively. (F) A structural comparison of the active site of PKM2 in R- and T-state tetramers. PKM2 in R- and T-state conformations are colored in yellow and blue, respectively

Mentions: Previous studies have demonstrated that a PKM2 tetramer in the R-state (active) is more active than that in the T-state (inactive). Structural comparison indicates that each individual monomer of PKM2 adopts similar fold with a root-mean-squared deviation (rmsd) of less than 0.6 Å for approximately 430 aligned Cα atoms (Fig. S2C). However, structure analysis indicates that the PKM2 tetramer undergoes significant changes between R- and T-state conformations with a rotation about the helix α9 of five degrees for each monomer (Fig. 2B and 2C). This observation is consistent with previous studies of the PKM protein in Leishmania Mexicana (Morgan et al., 2010). The PKM2 tetramer is formed through intermolecular interactions between four monomers on large (A-A′) and small (C-C′) interfaces (Fig. 2A). We propose a seesaw model for overall conformational changes during transitions between the R-state (PKM2K305Q) and the T-state (PKM2K422R) (Fig. 2B and 2C).Figure 2


Structural insight into mechanisms for dynamic regulation of PKM2.

Wang P, Sun C, Zhu T, Xu Y - Protein Cell (2015)

Crystal structure of human PKM2 and a “seesaw” model for conformational transitions of PKM2 tetramer. (A) Ribbon representation of the human PKM2 structure (PKM2K422R) with A-A′ (red box) and C-C′ (yellow box) interfaces indicated as dashed lines. Four monomers are shown in different colors. (B and C) A “seesaw” model for the conformational transitions between the R-state (B) and T-state (C) conformations of the PKM2 tetramer. Critical elements for the conformational changes are indicated. Dashed arrows indicate the directions for the rotation of each monomer from the R- (B) to the T- (C) state. The monomers are indicated as monomer A to D for simplicity in the following description. (D and E) A close-up view for the structural comparison of the PKM2 structure in the R- and T-state conformations on the C-C′ (D) or A-A′ (E) interface. PKM2 in R- and T-state conformations are colored in yellow and blue, respectively. (F) A structural comparison of the active site of PKM2 in R- and T-state tetramers. PKM2 in R- and T-state conformations are colored in yellow and blue, respectively
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Fig2: Crystal structure of human PKM2 and a “seesaw” model for conformational transitions of PKM2 tetramer. (A) Ribbon representation of the human PKM2 structure (PKM2K422R) with A-A′ (red box) and C-C′ (yellow box) interfaces indicated as dashed lines. Four monomers are shown in different colors. (B and C) A “seesaw” model for the conformational transitions between the R-state (B) and T-state (C) conformations of the PKM2 tetramer. Critical elements for the conformational changes are indicated. Dashed arrows indicate the directions for the rotation of each monomer from the R- (B) to the T- (C) state. The monomers are indicated as monomer A to D for simplicity in the following description. (D and E) A close-up view for the structural comparison of the PKM2 structure in the R- and T-state conformations on the C-C′ (D) or A-A′ (E) interface. PKM2 in R- and T-state conformations are colored in yellow and blue, respectively. (F) A structural comparison of the active site of PKM2 in R- and T-state tetramers. PKM2 in R- and T-state conformations are colored in yellow and blue, respectively
Mentions: Previous studies have demonstrated that a PKM2 tetramer in the R-state (active) is more active than that in the T-state (inactive). Structural comparison indicates that each individual monomer of PKM2 adopts similar fold with a root-mean-squared deviation (rmsd) of less than 0.6 Å for approximately 430 aligned Cα atoms (Fig. S2C). However, structure analysis indicates that the PKM2 tetramer undergoes significant changes between R- and T-state conformations with a rotation about the helix α9 of five degrees for each monomer (Fig. 2B and 2C). This observation is consistent with previous studies of the PKM protein in Leishmania Mexicana (Morgan et al., 2010). The PKM2 tetramer is formed through intermolecular interactions between four monomers on large (A-A′) and small (C-C′) interfaces (Fig. 2A). We propose a seesaw model for overall conformational changes during transitions between the R-state (PKM2K305Q) and the T-state (PKM2K422R) (Fig. 2B and 2C).Figure 2

Bottom Line: We determined crystal structures of human PKM2 mutants and proposed a "seesaw" model to illustrate conformational changes between an inactive T-state and an active R-state tetramers of PKM2.K422R, a patient-derived mutation of PKM2, favors a stable, inactive T-state tetramer because of strong intermolecular interactions.Our study reveals the mechanism for dynamic regulation of PKM2 by post-translational modifications and a patient-derived mutation and provides a structural basis for further investigation of other modifications and mutations of PKM2 yet to be discovered.

View Article: PubMed Central - PubMed

Affiliation: Fudan University Shanghai Cancer Center and Institute of Biomedical Sciences, Shanghai Medical College of Fudan University, Shanghai, 200032, China.

ABSTRACT
Pyruvate kinase isoform M2 (PKM2) converts phosphoenolpyruvate (PEP) to pyruvate and plays an important role in cancer metabolism. Here, we show that post-translational modifications and a patient-derived mutation regulate pyruvate kinase activity of PKM2 through modulating the conformation of the PKM2 tetramer. We determined crystal structures of human PKM2 mutants and proposed a "seesaw" model to illustrate conformational changes between an inactive T-state and an active R-state tetramers of PKM2. Biochemical and structural analyses demonstrate that PKM2(Y105E) (phosphorylation mimic of Y105) decreases pyruvate kinase activity by inhibiting FBP (fructose 1,6-bisphosphate)-induced R-state formation, and PKM2(K305Q) (acetylation mimic of K305) abolishes the activity by hindering tetramer formation. K422R, a patient-derived mutation of PKM2, favors a stable, inactive T-state tetramer because of strong intermolecular interactions. Our study reveals the mechanism for dynamic regulation of PKM2 by post-translational modifications and a patient-derived mutation and provides a structural basis for further investigation of other modifications and mutations of PKM2 yet to be discovered.

Show MeSH
Related in: MedlinePlus