7AIR

Structure of Human Potassium Chloride Transporter KCC1 in NaCl (Subclass 2)

Summary for 7AIR

• Entry DOI: 10.2210/pdb7air/pdb
• Related: 7AIP 7AIQ
• EMDB information: 11803
• Descriptor: Solute carrier family 12 member 4, beta-D-mannopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose, 2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose, ... (6 entities in total)
• Functional Keywords: ccc, transporter, human membrane protein, homodimer, nucleotide-binding, kcc1, kcc, potassium-chloride coupled transporter, structural genomics, structural genomics consortium, sgc, transport protein
• Biological source: Homo sapiens (Human); More
• Total number of polymer chains: 2
• Total formula weight: 242133.59

Authors

Ebenhoch, R.,Chi, G.,Man, H.,Wang, D.,McKinley, G.,Mukhopadhyay, S.M.M.,MacLean, E.M.,Chalk, R.,Moreau, C.,Snee, M.,Bohstedt, T.,Singh, N.K.,Abrusci, P.,Liko, I.,Tehan, B.G.,Almeida, F.G.,Arrowsmith, C.H.,Tang, H.,Robinson, C.V.,Bountra, C.,Edwards, A.M.,Marsden, B.D.,Burgess-Brown, N.A.,Duerr, K.L.,Structural Genomics Consortium (SGC) (deposition date: 2020-09-28, release date: 2021-06-02, Last modification date: 2021-07-28)

Primary citation

Chi, G.,Ebenhoch, R.,Man, H.,Tang, H.,Tremblay, L.E.,Reggiano, G.,Qiu, X.,Bohstedt, T.,Liko, I.,Almeida, F.G.,Garneau, A.P.,Wang, D.,McKinley, G.,Moreau, C.P.,Bountra, K.D.,Abrusci, P.,Mukhopadhyay, S.M.M.,Fernandez-Cid, A.,Slimani, S.,Lavoie, J.L.,Burgess-Brown, N.A.,Tehan, B.,DiMaio, F.,Jazayeri, A.,Isenring, P.,Robinson, C.V.,Durr, K.L.
Phospho-regulation, nucleotide binding and ion access control in potassium-chloride cotransporters.
Embo J., 40:e107294-e107294, 2021

PubMed Abstract: Potassium-coupled chloride transporters (KCCs) play crucial roles in regulating cell volume and intracellular chloride concentration. They are characteristically inhibited under isotonic conditions via phospho-regulatory sites located within the cytoplasmic termini. Decreased inhibitory phosphorylation in response to hypotonic cell swelling stimulates transport activity, and dysfunction of this regulatory process has been associated with various human diseases. Here, we present cryo-EM structures of human KCC3b and KCC1, revealing structural determinants for phospho-regulation in both N- and C-termini. We show that phospho-mimetic KCC3b is arrested in an inward-facing state in which intracellular ion access is blocked by extensive contacts with the N-terminus. In another mutant with increased isotonic transport activity, KCC1Δ19, this interdomain interaction is absent, likely due to a unique phospho-regulatory site in the KCC1 N-terminus. Furthermore, we map additional phosphorylation sites as well as a previously unknown ATP/ADP-binding pocket in the large C-terminal domain and show enhanced thermal stabilization of other CCCs by adenine nucleotides. These findings provide fundamentally new insights into the complex regulation of KCCs and may unlock innovative strategies for drug development.

PubMed: 34031912
DOI: 10.15252/embj.2020107294

Experimental method

ELECTRON MICROSCOPY (3.66 Å)