Structure of V-ATPase from the mammalian brain

In neurons, the loading of neurotransmitters into synaptic vesicles uses energy from proton-pumping vesicular- or vacuolar-type adenosine triphosphatases (V-ATPases). These membrane protein complexes possess numerous subunit isoforms, which complicates their analysis. We isolated homogeneous rat brain V-ATPase through its interaction with SidK, a Legionella pneumophila effector protein. Cryo–electron microscopy allowed the construction of an atomic model, defining the enzyme’s ATP:proton ratio as 3:10 and revealing a homolog of yeast subunit f in the membrane region, which we tentatively identify as RNAseK. The c ring encloses the transmembrane anchors for cleaved ATP6AP1/Ac45 and ATP6AP2/PRR, the latter of which is the (pro)renin receptor that, in other contexts, is involved in both Wnt signaling and the renin-angiotensin system that regulates blood pressure. This structure shows how ATP6AP1/Ac45 and ATP6AP2/PRR enable assembly of the enzyme’s catalytic and membrane regions.

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New approach for membrane protein reconstitution into peptidiscs and basis for their adaptability to different proteins

eLife ◽

10.7554/elife.53530 ◽

2020 ◽

Vol 9 ◽

Cited By ~ 4

Author(s):

Gabriella Angiulli ◽

Harveer Singh Dhupar ◽

Hiroshi Suzuki ◽

Irvinder Singh Wason ◽

Franck Duong Van Hoa ◽

...

Keyword(s):

Membrane Proteins ◽

Membrane Protein ◽

Protein Complexes ◽

Structural Basis ◽

New Approach ◽

Functional Studies ◽

Cryo Electron Microscopy ◽

High Resolution Structure ◽

Membrane Protein Complexes ◽

Membrane Protein Reconstitution

Previously we introduced peptidiscs as an alternative to detergents to stabilize membrane proteins in solution (Carlson et al., 2018). Here, we present ‘on-gradient’ reconstitution, a new gentle approach for the reconstitution of labile membrane-protein complexes, and used it to reconstitute Rhodobacter sphaeroides reaction center complexes, demonstrating that peptidiscs can adapt to transmembrane domains of very different sizes and shapes. Using the conventional ‘on-bead’ approach, we reconstituted Escherichia coli proteins MsbA and MscS and find that peptidiscs stabilize them in their native conformation and allow for high-resolution structure determination by cryo-electron microscopy. The structures reveal that peptidisc peptides can arrange around transmembrane proteins differently, thus revealing the structural basis for why peptidiscs can stabilize such a large variety of membrane proteins. Together, our results establish the gentle and easy-to-use peptidiscs as a potentially universal alternative to detergents as a means to stabilize membrane proteins in solution for structural and functional studies.

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Effects of renovascular hypertension on rat adrenal zona glomerulosa

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100083783 ◽

1978 ◽

Vol 36 (2) ◽

pp. 582-583

Author(s):

G. Mazzocchi ◽

P. Rebuffat ◽

C. Robba ◽

P. Vassanelli ◽

G. G. Nussdorfer

Keyword(s):

Renovascular Hypertension ◽

Left Kidney ◽

Renin Angiotensin System ◽

Plasma Renin ◽

Zona Glomerulosa ◽

Ultrastructural Changes ◽

Albino Rats ◽

Left Renal Artery ◽

Angiotensin System ◽

And Control

It is well known that the rat adrenal zona glomerulosa steroidogenic activity is controlled by the renin-angiotensin system. The ultrastructural changes in the rat zona glomerulosa cells induced by renovascular hypertension were described previously, but as far as we are aware no correlated biochemical and morphometric investigations were performed.Twenty adult male albino rats were divided into 2 experimental groups. One group was subjected to restriction of blood flow to the left kidney by the application of a silver clip about the left renal artery. The other group was sham-operated and served as a control. Renovascular hypertension developed in about 10 days: sistolic blood pressure averaged 165 ± 6. 4 mmHg, whereas it was about 110 ± 3. 8 mmHg in the control animals. The hypertensive and control rats were sacrificed 20 days after the operation. The blood was collected and plasma renin activity was determined by radioimmunological methods. The aldosterone concentration was radioimmunologically assayed both in the plasma and in the homogenate of the left capsular adrenal gland.

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