Cryo-EM structures of the full-length human KCC2 and KCC3 cation-chloride cotransporters

Chi, Ximin; Li, Xiaorong; Chen, Yun; Zhang, Yuanyuan; Su, Qiang; Zhou, Qiang

doi:10.1038/s41422-020-00437-x

Cited by 38 publications

(63 citation statements)

References 12 publications

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“…As confirmed by recent cryo-EM [126][127][128][129][130][131][132] and X-ray crystal structure [140], CCCs exist as dimers, and both the cytoplasmic C-terminal and transmembrane domains are involved in dimerization. Thus, KCC2a heterodimerization with KCC2b in vivo [34] (and the tight interaction of the C-termini within dimers) might allow SPAK/OSR1 to phosphorylate the C-terminal threonines of both KCC2 variants in the heterodimer.…”

Section: Box 3 Phosphorylation Of Kcc2: Role Of Splice Variantsmentioning

confidence: 72%

“…The swapping occurs in the 'scissor helix' region that connects TMD and CTD within each subunit, as shown for all hKCCs [129,130] and DrNKCC1 [126]. The extracellular domains stabilize hKCC1 [129,130] but not hKCC2, hKCC3, or hKCC4 dimers [131,132]. It is worth pointing out here that the SDS-resistant higher homo-oligomers of KCC2 in western blots are obviously a result of the well-known aggregation of membrane proteins subjected to heating or acidic pH [134].…”

Section: Molecular Structure Of Cccsmentioning

confidence: 83%

“…Despite the fact that CCCs were cloned >20 years ago, their tertiary and quaternary structures remained unknown until very recently. The development of cryogenic electron microscopy (cryo-EM) and single-particle image processing brought several reports describing high-resolution structures of zebrafish [126] and human [127] NKCC1, mouse KCC4 [128], as well as human KCC1 [129,130], KCC2/KCC3 [131], and KCC2/KCC3/KCC4 [132].…”

Section: Molecular Structure Of Cccsmentioning

confidence: 99%

“…The N-terminal domains of CCCs yield poor resolution by EM, indicating high conformational flexibility. Interestingly, the human KCC2/KCC3 [131] and KCC2/KCC4 [132] structures have a~25 amino acid N-terminal loop that blocks the cytoplasmic entry of the translocation pore. Consistent with the function of this loop as a modulator of the transporter, its deletion [131] or mutation [132] activated ion transport.…”

Section: Molecular Structure Of Cccsmentioning

confidence: 99%

“…Only the KCC2a isoform contains the conserved SPAK/OSR1 binding site (RFTV). The autoinhibitory N-terminal loop (A66-N83 in KCC2b[131] and V81-N107 in KCC2a[132], Box 1) (red) in the entry of the cytosolic vestibule functions as a blocker. The amino acid numbering in the figure is according to the human KCC2b isoform.…”

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confidence: 99%

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The Multifaceted Roles of KCC2 in Cortical Development

Virtanen

Uvarov

Mavrović

et al. 2021

Trends in Neurosciences

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KCC2, best known as the neuron-specific chloride-extruder that sets the strength and polarity of GABAergic currents during neuronal maturation, is a multifunctional molecule that can regulate cytoskeletal dynamics via its C-terminal domain (CTD). We describe the molecular and cellular mechanisms involved in the multiple functions of KCC2 and its splice variants, ranging from developmental apoptosis and the control of early network events to the formation and plasticity of cortical dendritic spines. The versatility of KCC2 actions at the cellular and subcellular levels is also evident in mature neurons during plasticity, disease, and aging. Thus, KCC2 has emerged as one of the most important molecules that shape the overall neuronal phenotype. KCC2 in the Fundamental Machinery Underlying Neuronal Development, Signaling, and StructureFast synaptic transmission relies on ion fluxes through ligand-gated ion channels. Although the default state of a cell is to have a high intracellular chloride concentration ([Cl − ] i ), mature neurons in the CNS have evolved a unique ability to maintain a low [Cl − ] i , which is needed for the generation of hyperpolarizing Cl − currents across GABA A and glycine receptors (GABA A Rs and GlyRs) [1]. This specialization comes at a high energy cost [2], and is brought about by upregulation of the neuron-specific K-Cl cotransporter KCC2 during neuronal maturation [1,3,4]. KCC2 belongs to the evolutionarily ancient family of SLC12 cation/chloride cotransporters (CCCs) (Box 1; for KCCs and NKCCs, see Glossary) that have their roots in a single gene in Archaea, from which numerous duplication events in both archaeans and eukaryotes have led to the divergence and neofunctionalization of the paralogous CCC subfamilies [5]. Possibly because of a primordial role in cellular volume regulation, CCCs have evolved to communicate with the actin cytoskeleton. Indeed, KCC2 has emerged as an important player in controlling actin dynamics during neuronal development and plasticity [6][7][8][9].The functional upregulation of KCC2-mediated K-Cl cotransport in hippocampal and neocortical neurons underlies the hyperpolarizing shift in GABAergic currents which takes place postnatally in rats and mice [3], but it has become clear that KCC2 is expressed at low but functionally significant levels pre-and perinatally. KCC2 acts in an ion transport-independent manner as an antiapoptotic factor in projection neurons in the prenatal mouse neocortex [10]; in the perinatal mouse and rat hippocampus transport-functional KCC2 decreases the depolarizing driving force of GABA A R-mediated currents (DF GABA ), thereby influencing spontaneous network events at their developmental onset [11].In this review we highlight the developmental paths from KCC2 protein expression to its multiple functions, and discuss the wide variety of post-translational mechanisms which control these phenomena. The versatility of KCC2 regulation at the cellular and subcellular levels is also evident in mature neurons during plasticity, disease,...

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Section: Box 3 Phosphorylation Of Kcc2: Role Of Splice Variantsmentioning

confidence: 72%

Section: Molecular Structure Of Cccsmentioning

confidence: 83%

Section: Molecular Structure Of Cccsmentioning

confidence: 99%

Section: Molecular Structure Of Cccsmentioning

confidence: 99%

mentioning

confidence: 99%

See 3 more Smart Citations

The Multifaceted Roles of KCC2 in Cortical Development

Virtanen

Uvarov

Mavrović

et al. 2021

Trends in Neurosciences

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New and Emerging Research on Solute Carrier and ATP Binding Cassette Transporters in Drug Discovery and Development: Outlook From the International Transporter Consortium

Giacomini

Yee

Koleske

et al. 2022

Clin Pharma and Therapeutics

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Enabled by a plethora of new technologies, research in membrane transporters has exploded in the past decade. The goal of this state‐of‐the‐art article is to describe recent advances in research on membrane transporters that are particularly relevant to drug discovery and development. This review covers advances in basic, translational, and clinical research that has led to an increased understanding of membrane transporters at all levels. At the basic level, we describe the available crystal structures of membrane transporters in both the solute carrier (SLC) and ATP binding cassette superfamilies, which has been enabled by the development of cryogenic electron microscopy methods. Next, we describe new research on lysosomal and mitochondrial transporters as well as recently deorphaned transporters in the SLC superfamily. The translational section includes a summary of proteomic research, which has led to a quantitative understanding of transporter levels in various cell types and tissues and new methods to modulate transporter function, such as allosteric modulators and targeted protein degraders of transporters. The section ends with a review of the effect of the gut microbiome on modulation of transporter function followed by a presentation of 3D cell cultures, which may enable in vivo predictions of transporter function. In the clinical section, we describe new genomic and pharmacogenomic research, highlighting important polymorphisms in transporters that are clinically relevant to many drugs. Finally, we describe new clinical tools, which are becoming increasingly available to enable precision medicine, with the application of tissue‐derived small extracellular vesicles and real‐world biomarkers.

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