Membrane orientation of the Na,K-ATPase regulatory membrane protein CHIF determined by solid-state NMR

Franzin, Carla M.; Teriete, Peter; Marassi, Francesca M.

doi:10.1002/mrc.2144

Cited by 3 publications

(1 citation statement)

References 33 publications

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“…Secondary structure dependent patterns are expected for RDC spectra [25] which allows the direct comparison of secondary structure topologies determined from both solution and solid state NMR. These techniques are becoming common for membrane proteins [26][27][28][29]14]. …”

Section: Nmr Orientational Restraintsmentioning

confidence: 99%

Geometry of kinked protein helices from NMR data

Murray

Cross

et al. 2011

Journal of Magnetic Resonance

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Section: Nmr Orientational Restraintsmentioning

confidence: 99%

Geometry of kinked protein helices from NMR data

Murray

Cross

et al. 2011

Journal of Magnetic Resonance

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A study of the membrane association and regulatory effect of the phospholemman cytoplasmic domain

Hughes¹,

Whittaker²,

Barsukov³

et al. 2011

Biochimica et Biophysica Acta (BBA) - Biomembranes

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Phospholemman (PLM) is a single-span transmembrane protein belonging to the FXYD family of proteins. PLM (or FXYD1) regulates the Na,K-ATPase (NKA) ion pump by altering its affinity for K(+) and Na(+) and by reducing its hydrolytic activity. Structural studies of PLM in anionic detergent micelles have suggested that the cytoplasmic domain, which alone can regulate NKA, forms a partial helix which is stabilized by interactions with the charged membrane surface. This work examines the membrane affinity and regulatory function of a 35-amino acid peptide (PLM(38-72)) representing the PLM cytoplasmic domain. Isothermal titration calorimetry and solid-state NMR measurements confirm that PLM(38-72) associates strongly with highly anionic phospholipid membranes, but the association is weakened substantially when the negative surface charge is reduced to a more physiologically relevant environment. Membrane interactions are also weakened when the peptide is phosphorylated at S68, one of the substrate sites for protein kinases. PLM(38-72) also lowers the maximal velocity of ATP hydrolysis (V(max)) by NKA, and phosphorylation of the peptide at S68 gives rise to a partial recovery of V(max). These results suggest that the PLM cytoplasmic domain populates NKA-associated and membrane-associated states in dynamic equilibrium and that phosphorylation may alter the position of the equilibrium. Interestingly, peptides representing the cytoplasmic domains of two other FXYD proteins, Mat-8 (FXYD3) and CHIF (FXYD4), have little or no interaction with highly anionic phospholipid membranes and have no effect on NKA function. This suggests that the functional and physical properties of PLM are not conserved across the entire FXYD family.

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