Dataset Information

Osmosensing and scaffolding functions of the oligomeric four-transmembrane domain osmosensor Sho1.

ABSTRACT: The yeast high osmolarity glycerol (HOG) pathway activates the Hog1 MAP kinase, which coordinates adaptation to high osmolarity conditions. Here we demonstrate that the four-transmembrane (TM) domain protein Sho1 is an osmosensor in the HKR1 sub-branch of the HOG pathway. Crosslinking studies indicate that Sho1 forms planar oligomers of the dimers-of-trimers architecture by dimerizing at the TM1/TM4 interface and trimerizing at the TM2/TM3 interface. High external osmolarity induces structural changes in the Sho1 TM domains and Sho1 binding to the cytoplasmic adaptor protein Ste50, which leads to Hog1 activation. Besides its osmosensing function, the Sho1 oligomer serves as a scaffold. By binding to the TM proteins Opy2 and Hkr1 at the TM1/TM4 and TM2/TM3 interface, respectively, Sho1 forms a multi-component signalling complex that is essential for Hog1 activation. Our results illuminate how the four TM domains of Sho1 dictate the oligomer structure as well as its osmosensing and scaffolding functions.

SUBMITTER: Tatebayashi K

PROVIDER: S-EPMC4411306 | biostudies-other | 2015

REPOSITORIES: biostudies-other

ACCESS DATA

Publications

Osmosensing and scaffolding functions of the oligomeric four-transmembrane domain osmosensor Sho1.

Tatebayashi Kazuo K Yamamoto Katsuyoshi K Nagoya Miho M Takayama Tomomi T Nishimura Akiko A Sakurai Megumi M Momma Takashi T Saito Haruo H

Nature communications 20150421

The yeast high osmolarity glycerol (HOG) pathway activates the Hog1 MAP kinase, which coordinates adaptation to high osmolarity conditions. Here we demonstrate that the four-transmembrane (TM) domain protein Sho1 is an osmosensor in the HKR1 sub-branch of the HOG pathway. Crosslinking studies indicate that Sho1 forms planar oligomers of the dimers-of-trimers architecture by dimerizing at the TM1/TM4 interface and trimerizing at the TM2/TM3 interface. High external osmolarity induces structural c ...[more]

PMID: 25898136

Similar Datasets

Project description:The HIV-1 glycoprotein, gp41, mediates fusion of the virus lipid envelope with the target cell membrane during virus entry into cells. Despite extensive studies of this protein, inconsistent and contradictory structural information abounds in the literature about the C-terminal membrane-interacting region of gp41. This C-terminal region contains the membrane-proximal external region (MPER), which harbors the epitopes for four broadly neutralizing antibodies, and the transmembrane domain (TMD), which anchors the protein to the virus lipid envelope. Due to the difficulty of crystallizing and solubilizing the MPER-TMD, most structural studies of this functionally important domain were carried out using truncated peptides either in the absence of membrane-mimetic solvents or bound to detergents and lipid bicelles. To determine the structural architecture of the MPER-TMD in the native environment of lipid membranes, we have now carried out a solid-state NMR study of the full MPER-TMD segment bound to cholesterol-containing phospholipid bilayers. 13C chemical shifts indicate that the majority of the peptide is α-helical, except for the C-terminus of the TMD, which has moderate β-sheet character. Intermolecular 19F-19F distance measurements of singly fluorinated peptides indicate that the MPER-TMD is trimerized in the virus-envelope mimetic lipid membrane. Intramolecular 13C-19F distance measurements indicate the presence of a turn between the MPER helix and the TMD helix. This is supported by lipid-peptide and water-peptide 2D 1H-13C correlation spectra, which indicate that the MPER binds to the membrane surface whereas the TMD spans the bilayer. Together, these data indicate that full-length MPER-TMD assembles into a trimeric helix-turn-helix structure in lipid membranes. We propose that the turn between the MPER and TMD may be important for inducing membrane defects in concert with negative-curvature lipid components such as cholesterol and phosphatidylethanolamine, while the surface-bound MPER helix may interact with N-terminal segments of the protein during late stages of membrane fusion.

Dataset Information

Osmosensing and scaffolding functions of the oligomeric four-transmembrane domain osmosensor Sho1.

Publications

Osmosensing and scaffolding functions of the oligomeric four-transmembrane domain osmosensor Sho1.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets