Identification of an autoinhibitory, mitophagy-inducing peptide derived from the transmembrane domain of USP30

SummaryRecombinant human soluble thrombomodulin (rhs-TM), having no transmembrane domain or chondroitin sulfate, was expressed in Chinese hamster ovary cells. Interactions between rhs-TM, thrombin (Th), protein C (PC) and antithrombin III (ATIII) were studied. Equilibrium between rhs-TM and Th had no detectable time lag in clotting inhibition (K d = 26 nM) or PC activation (K d = 22 nM), while ATIII inhibited Th at a bimolecular rate constant = 5,200 M-1s-1 (K d <0.2 nM). A mixture of ATIII, Th and rhs-TM showed that ATIII reacted with Th slower than rhs-TM, whose presence did not affect the reaction between ATIII and Th. In a mixture of rhs-TM, ATIII and PC, the repeated addition of Th caused the repeated activation of PC; which was consistent with the Simulation based on the assumption that rhs-TM is recycled as a Th cofactor. From these results, we concluded that upon inhibition of the rhs-TM-Th complex by ATIII, rhs-TM is released to recombine with free Th and begins to activate PC, while the Th-ATIII complex does not affect rhs-TM-Th equilibrium.

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Structural and Dynamic Study of the Transmembrane Domain of the Amyloid Precursor Protein

Acta Naturae ◽

10.32607/20758251-2011-3-1-69-76 ◽

2011 ◽

Vol 3 (1) ◽

pp. 69-76 ◽

Cited By ~ 40

Author(s):

K D Nadezhdin ◽

O V Bocharova ◽

E V Bocharov ◽

A S Arseniev

Keyword(s):

Amyloid Precursor Protein ◽

Transmembrane Domain ◽

Dynamic Study ◽

Precursor Protein

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Somatic transmembrane domain mutations of a cell adhesion molecule, CADM1, cause primary aldosteronism by preventing gap junction communication between adrenocortical cells

Endocrine Abstracts ◽

10.1530/endoabs.65.oc5.5 ◽

2019 ◽

Author(s):

Xilin Wu ◽

Sumedha Garg ◽

Claudia Cabrera ◽

Elena Azizan ◽

Junhua Zhou ◽

...

Keyword(s):

Cell Adhesion ◽

Gap Junction ◽

Adhesion Molecule ◽

Primary Aldosteronism ◽

Cell Adhesion Molecule ◽

Transmembrane Domain ◽

Adrenocortical Cells ◽

Gap Junction Communication ◽

A Cell

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Constant pH Molecular Dynamics Reveals How Proton Release Drives the Conformational Transition of a Transmembrane Efflux Pump

10.26434/chemrxiv.5496907 ◽

2017 ◽

Author(s):

Jana Shen ◽

Zhi Yue ◽

Helen Zgurskaya ◽

Wei Chen

Keyword(s):

Molecular Dynamics ◽

Conformational Changes ◽

Transmembrane Domain ◽

Conformational Transition ◽

Conformational Dynamics ◽

Proton Release ◽

Intrinsic Resistance ◽

Constant Ph ◽

Wide Range ◽

Constant Ph Molecular Dynamics

AcrB is the inner-membrane transporter of E. coli AcrAB-TolC tripartite efflux complex, which plays a major role in the intrinsic resistance to clinically important antibiotics. AcrB pumps a wide range of toxic substrates by utilizing the proton gradient between periplasm and cytoplasm. Crystal structures of AcrB revealed three distinct conformational states of the transport cycle, substrate access, binding and extrusion, or loose (L), tight (T) and open (O) states. However, the specific residue(s) responsible for proton binding/release and the mechanism of proton-coupled conformational cycling remain controversial. Here we use the newly developed membrane hybrid-solvent continuous constant pH molecular dynamics technique to explore the protonation states and conformational dynamics of the transmembrane domain of AcrB. Simulations show that both Asp407 and Asp408 are deprotonated in the L/T states, while only Asp408 is protonated in the O state. Remarkably, release of a proton from Asp408 in the O state results in large conformational changes, such as the lateral and vertical movement of transmembrane helices as well as the salt-bridge formation between Asp408 and Lys940 and other sidechain rearrangements among essential residues.Consistent with the crystallographic differences between the O and L protomers, simulations offer dynamic details of how proton release drives the O-to-L transition in AcrB and address the controversy regarding the proton/drug stoichiometry. This work offers a significant step towards characterizing the complete cycle of proton-coupled drug transport in AcrB and further validates the membrane hybrid-solvent CpHMD technique for studies of proton-coupled transmembrane proteins which are currently poorly understood. <p><br></p>

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