Structural mechanism underlying the differential effects of ivermectin and moxidectin on the C. elegans glutamate-gated chloride channel GLC-2

Endocytosis of transmembrane proteins is orchestrated by the AP2 clathrin adaptor complex. AP2 dwells in a closed, inactive state in the cytosol, but adopts an open, active conformation on the plasma membrane. Membrane-activated complexes are also phosphorylated, but the significance of this mark is debated. We recently proposed that NECAP negatively regulates AP2 by binding open and phosphorylated complexes (Beacham et al., 2018). Here, we report high-resolution cryo-EM structures of NECAP bound to phosphorylated AP2. The site of AP2 phosphorylation is directly coordinated by residues of the NECAP PHear domain that are predicted from genetic screens in C. elegans. Using membrane mimetics to generate conformationally open AP2, we find that a second domain of NECAP binds these complexes and cryo-EM reveals both domains of NECAP engaging closed, inactive AP2. Assays in vitro and in vivo confirm these domains cooperate to inactivate AP2. We propose that phosphorylation marks adaptors for inactivation.

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A structural mechanism for phosphorylation-dependent inactivation of the AP2 complex

10.1101/701532 ◽

2019 ◽

Author(s):

Edward A. Partlow ◽

Richard W. Baker ◽

Gwendolyn M. Beacham ◽

Joshua S. Chappie ◽

Andres E. Leschziner ◽

...

Keyword(s):

Plasma Membrane ◽

Transmembrane Proteins ◽

Active Conformation ◽

Genetic Screens ◽

Structural Mechanism ◽

C Elegans ◽

Dependent Inactivation ◽

Clathrin Adaptor

AbstractEndocytosis of transmembrane proteins is orchestrated by the AP2 clathrin adaptor complex. AP2 dwells in a closed, inactive state in the cytosol, but adopts an open, active conformation on the plasma membrane. Membrane-activated complexes are also phosphorylated, but the significance of this mark is debated. We recently proposed that NECAP negatively regulates AP2 by binding open and phosphorylated complexes (Beacham et al., 2018). Here, we report high-resolution cryo-EM structures of NECAP bound to phosphorylated AP2. The site of AP2 phosphorylation is directly coordinated by residues of the NECAP PHear domain that are predicted from genetic screens in C. elegans. Using membrane mimetics to generate conformationally open AP2, we find that a second domain of NECAP binds these complexes and cryo-EM reveals both domains of NECAP engaging closed, inactive AP2. Assays in vitro and in vivo confirm these domains cooperate to inactivate AP2. We propose that phosphorylation marks adaptors for inactivation.

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Roles of the ClC chloride channel CLH-1 in food-associated salt chemotaxis behavior of C. elegans

eLife ◽

10.7554/elife.55701 ◽

2021 ◽

Vol 10 ◽

Author(s):

Chanhyun Park ◽

Yuki Sakurai ◽

Hirofumi Sato ◽

Shinji Kanda ◽

Yuichi Iino ◽

...

Keyword(s):

Chloride Channel ◽

Regulatory Mechanism ◽

Ion Homeostasis ◽

Sensory Information ◽

Fluorescent Sensors ◽

Neural Mechanisms ◽

Anion Channels ◽

C Elegans ◽

Clc Chloride Channel ◽

Navigation Strategies

The ability of animals to process dynamic sensory information facilitates foraging in an ever-changing environment. However, molecular and neural mechanisms underlying such ability remain elusive. The ClC anion channels/transporters play a pivotal role in cellular ion homeostasis across all phyla. Here, we find a ClC chloride channel is involved in salt concentration chemotaxis of Caenorhabditis elegans. Genetic screening identified two altered-function mutations of clh-1 that disrupt experience-dependent salt chemotaxis. Using genetically encoded fluorescent sensors, we demonstrate that CLH-1 contributes to regulation of intracellular anion and calcium dynamics of salt-sensing neuron, ASER. The mutant CLH-1 reduced responsiveness of ASER to salt stimuli in terms of both temporal resolution and intensity, which disrupted navigation strategies for approaching preferred salt concentrations. Furthermore, other ClC genes appeared to act redundantly in salt chemotaxis. These findings provide insights into the regulatory mechanism of neuronal responsivity by ClCs that contribute to modulation of navigation behavior.

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Function follows form: Differential effects on respiratory capacity of 13 nuclear-encoded subunits of mitochondrial complex I in C. elegans

Mitochondrion ◽

10.1016/j.mito.2006.08.017 ◽

2006 ◽

Vol 6 (5) ◽

pp. 270

Author(s):

M.J. Falk ◽

J. Rosenjack ◽

M.A. O’Riordan ◽

M.M. Sedensky ◽

P.G. Morgan

Keyword(s):

Complex I ◽

Mitochondrial Complex I ◽

Mitochondrial Complex ◽

Respiratory Capacity ◽

Differential Effects ◽

C Elegans

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Roles of the ClC Chloride Channel CLH-1 in Food-associated Salt Chemotaxis Behavior of C. elegans

10.1101/2020.02.16.951368 ◽

2020 ◽

Author(s):

Chanhyun Park ◽

Yuki Sakurai ◽

Hirofumi Sato ◽

Shinji Kanda ◽

Yuichi Iino ◽

...

Keyword(s):

Salt Concentration ◽

Chloride Channel ◽

Ion Homeostasis ◽

Sensory Information ◽

Fluorescent Sensors ◽

Neural Mechanisms ◽

Anion Channels ◽

C Elegans ◽

Clc Chloride Channel ◽

Navigation Strategies

AbstractThe ability of animals to process dynamic sensory information facilitates foraging in an ever changing environment. However, molecular and neural mechanisms underlying such ability remain elusive. The ClC anion channels/transporters play a pivotal role in cellular ion homeostasis across all phlya. Here we find a ClC chloride channel is involved in salt concentration chemotaxis of C. elegans. Genetic screening identified two altered-function mutations of clh-1 that disrupt experience-dependent salt chemotaxis. Using genetically encoded fluorescent sensors, we demonstrate that CLH-1 contributes to regulation of chloride and calcium dynamics of salt-sensing neuron, ASER. The mutant CLH-1 reduced responsiveness of ASER to salt stimuli in terms of both temporal resolution and intensity, which could disrupt navigation strategies for approaching preferred salt concentration. Furthermore, other ClC genes appeared to act redundantly in salt chemotaxis. These findings provide insights into the regulatory mechanism of neuronal responsivity by ClCs that contribute to modulation of navigation behavior.

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