Solution Structure of Calmodulin Bound to the Binding Domain of the HIV-1 Matrix Protein

Vlach, Jiří; Samal, Alexandra B.; Saad, Jamil S.

doi:10.1074/jbc.m113.543694

Cited by 23 publications

(28 citation statements)

References 93 publications

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“…In both cases, the distance between the centers of the two CaM-binding pockets (C-domain and N-domain) is approximately 36Å, which corresponds to the 34Å distance from the β3/β4 loop to the β5/β6 loop in the Itk PH domain. The CaM-MA complex structure also reveals that CaM binding modulates the fold of the MA domain (47), which we anticipate could also occur for the Itk PH domain leading to the induction of helix formation of the large β3/β4 and β5/β6 loops for optimal CaM binding.…”

Section: Discussionmentioning

confidence: 88%

“…3B and C), may mediate binding to full-length CaM in a manner that requires CaM to maintain a semi-extended conformation rather than the collapsed conformation typical of many CaM-mediated interactions. Precedence for CaM engaging its targets in an extended fashion include the synaptic vesicle priming protein, Munc13 (19), and the structure of CaM bound to the matrix (MA) domain of the HIV-1 Gag protein (47). In both cases, the distance between the centers of the two CaM-binding pockets (C-domain and N-domain) is approximately 36Å, which corresponds to the 34Å distance from the β3/β4 loop to the β5/β6 loop in the Itk PH domain.…”

Section: Discussionmentioning

confidence: 99%

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Calmodulin and PI(3,4,5)P ₃ cooperatively bind to the Itk pleckstrin homology domain to promote efficient calcium signaling and IL-17A production

Wang

Boyken

et al. 2014

Sci. Signal.

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Precise regulation of the kinetics and magnitude of Ca2+ signaling enables this signal to mediate diverse responses, such as cell migration, differentiation, vesicular trafficking, and cell death. Here, we showed that the Ca2+-binding protein calmodulin (CaM) acted in a positive feedback loop to potentiate Ca2+ signaling downstream of the Tec kinase family member Itk. Using NMR (nuclear magnetic resonance), we mapped CaM binding to two loops adjacent to the lipid-binding pocket within the Itk pleckstrin homology (PH) domain. The Itk PH domain bound synergistically to Ca2+/CaM and the lipid phosphatidylinositol-3,4,5-trisphosphate [PI(3,4,5)P3], such that binding to Ca2+/CaM enhanced the binding to PI(3,4,5)P3 and vice versa. Disruption of CaM binding attenuated Itk recruitment to the membrane and diminished release of Ca2+ from the endoplasmic reticulum. Moreover, disruption of this feedback loop abrogated Itk-dependent production of the proinflammatory cytokine IL-17A (interleukin-17A) by CD4+ T cells. Additionally, we found that CaM associated with PH domains from other proteins, indicating that CaM may regulate other PH domain–containing proteins.

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Section: Discussionmentioning

confidence: 88%

Section: Discussionmentioning

confidence: 99%

Calmodulin and PI(3,4,5)P ₃ cooperatively bind to the Itk pleckstrin homology domain to promote efficient calcium signaling and IL-17A production

Wang

Boyken

et al. 2014

Sci. Signal.

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“…The repeated alternate binding of δ to first a single CBD and then to two could produce such a result. Multiple non‐contiguous interactions between CaM and several of its protein targets have been characterized, e.g., small conductance Ca 2+ ‐activated potassium channels . Unlike most CaM targets, both the potassium channel and PhK bind CaM in the absence of Ca 2+ , but are activated only in its presence .…”

Section: Resultsmentioning

confidence: 99%

Structural characterization of the catalytic γ and regulatory β subunits of phosphorylase kinase in the context of the hexadecameric enzyme complex

et al. 2017

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In the tightly regulated glycogenolysis cascade, the breakdown of glycogen to glucose-1-phosphate, phosphorylase kinase (PhK) plays a key role in regulating the activity of glycogen phosphorylase. PhK is a 1.3 MDa hexadecamer, with four copies each of four different subunits (α, β, γ and δ), making the study of its structure challenging. Using hydrogen-deuterium exchange, we have analyzed the regulatory β subunit and the catalytic γ subunit in the context of the intact non-activated PhK complex to study the structure of these subunits and identify regions of surface exposure. Our data suggest that within the non-activated complex the γ subunit assumes an activated conformation and are consistent with a previous docking model of the β subunit within the cryoelectron microscopy envelope of PhK.

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“…It was reported that a drastic structural change in helices 1 and 2 occurs upon binding to calmodulin[57,58]. It suggests the possibility that the dynamic structure of the α1–2 loop between helices 1 and 2 could be related to calmodulin binding.…”

Section: Discussionmentioning

confidence: 99%

Effect of Glu12-His89 Interaction on Dynamic Structures in HIV-1 p17 Matrix Protein Elucidated by NMR

et al. 2016

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To test the existence of the salt bridge and stability of the HIV-1 p17 matrix protein, an E12A (mutated at helix 1) was established to abolish possible electrostatic interactions. The chemical shift perturbation from the comparison between wild type and E12A suggested the existence of an electrostatic interaction in wild type between E12 and H89 (located in helix 4). Unexpectedly, the studies using urea denaturation indicated that the E12A substitution slightly stabilized the protein. The dynamic structure of E12A was examined under physiological conditions by both amide proton exchange and relaxation studies. The quick exchange method of amide protons revealed that the residues with faster exchange were located at the mutated region, around A12, compared to those of the wild-type protein. In addition, some residues at the region of helix 4, including H89, exhibited faster exchange in the mutant. In contrast, the average values of the kinetic rate constants for amide proton exchange for residues located in all loop regions were slightly lower in E12A than in wild type. Furthermore, the analyses of the order parameter revealed that less flexible structures existed at each loop region in E12A. Interestingly, the structures of the regions including the alpha1-2 loop and helix 5 of E12A exhibited more significant conformational exchanges with the NMR time-scale than those of wild type. Under lower pH conditions, for further destabilization, the helix 1 and alpha2-3 loop in E12A became more fluctuating than at physiological pH. Because the E12A mutant lacks the activities for trimer formation on the basis of the analytical ultra-centrifuge studies on the sedimentation distribution of p17 (Fledderman et al. Biochemistry 49, 9551–9562, 2010), it is possible that the changes in the dynamic structures induced by the absence of the E12-H89 interaction in the p17 matrix protein contributes to a loss of virus assembly.

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Solution Structure of Calmodulin Bound to the Binding Domain of the HIV-1 Matrix Protein

Cited by 23 publications

References 93 publications

Calmodulin and PI(3,4,5)P ₃ cooperatively bind to the Itk pleckstrin homology domain to promote efficient calcium signaling and IL-17A production

Calmodulin and PI(3,4,5)P ₃ cooperatively bind to the Itk pleckstrin homology domain to promote efficient calcium signaling and IL-17A production

Structural characterization of the catalytic γ and regulatory β subunits of phosphorylase kinase in the context of the hexadecameric enzyme complex

Effect of Glu12-His89 Interaction on Dynamic Structures in HIV-1 p17 Matrix Protein Elucidated by NMR

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Solution Structure of Calmodulin Bound to the Binding Domain of the HIV-1 Matrix Protein

Cited by 23 publications

References 93 publications

Calmodulin and PI(3,4,5)P 3 cooperatively bind to the Itk pleckstrin homology domain to promote efficient calcium signaling and IL-17A production

Calmodulin and PI(3,4,5)P 3 cooperatively bind to the Itk pleckstrin homology domain to promote efficient calcium signaling and IL-17A production

Structural characterization of the catalytic γ and regulatory β subunits of phosphorylase kinase in the context of the hexadecameric enzyme complex

Effect of Glu12-His89 Interaction on Dynamic Structures in HIV-1 p17 Matrix Protein Elucidated by NMR

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Calmodulin and PI(3,4,5)P ₃ cooperatively bind to the Itk pleckstrin homology domain to promote efficient calcium signaling and IL-17A production

Calmodulin and PI(3,4,5)P ₃ cooperatively bind to the Itk pleckstrin homology domain to promote efficient calcium signaling and IL-17A production