BAR Domain Proteins Regulate Rho GTPase Signaling

2018 ◽  
pp. 33-53 ◽  
Author(s):  
Pontus Aspenström
Keyword(s):  
Rho Gtpase ◽  
Bar Domain ◽  
Bar Domain Proteins

scholarly journals Membrane curvature directs the localization of Cdc42p to novel foci required for cell–cell fusion

2017 ◽  
Vol 216 (12) ◽  
pp. 3971-3980 ◽  
Author(s):  
Jean A. Smith ◽  
Allison E. Hall ◽  
Mark D. Rose
Keyword(s):  
Cell Fusion ◽  
Fusion Proteins ◽  
Cell Walls ◽  
Rho Gtpase ◽  
Membrane Curvature ◽  
Cell Wall Degradation ◽  
Focus Formation ◽  
Mutant Analysis ◽  
Bar Domain ◽  
Bar Domain Proteins

Cell fusion is ubiquitous in eukaryotic fertilization and development. The highly conserved Rho–GTPase Cdc42p promotes yeast fusion through interaction with Fus2p, a pheromone-induced amphiphysin-like protein. We show that in prezygotes, Cdc42p forms a novel Fus2p-dependent focus at the center of the zone of cell fusion (ZCF) and remains associated with remnant cell walls after initial fusion. At the ZCF and during fusion, Cdc42p and Fus2p colocalized. In contrast, in shmoos, both proteins were near the cortex but spatially separate. Cdc42p focus formation depends on ZCF membrane curvature: mutant analysis showed that Cdc42p localization is negatively affected by shmoo-like positive ZCF curvature, consistent with the flattening of the ZCF during fusion. BAR-domain proteins such as the fusion proteins Fus2p and Rvs161p are known to recognize membrane curvature. We find that mutations that disrupt binding of the Fus2p/Rvs161p heterodimer to membranes affect Cdc42p ZCF localization. We propose that Fus2p localizes Cdc42p to the flat ZCF to promote cell wall degradation.

scholarly journals BAR domain proteins regulate Rho GTPase signaling

Small GTPases ◽  
2014 ◽  
Vol 5 (2) ◽  
pp. e972854 ◽  
Author(s):  
Pontus Aspenström
Keyword(s):  
Rho Gtpase ◽  
Bar Domain ◽  
Bar Domain Proteins

scholarly journals FAM92A1 is a BAR domain protein required for mitochondrial ultrastructure and function

2018 ◽  
Vol 218 (1) ◽  
pp. 97-111 ◽  
Author(s):  
Liang Wang ◽  
Ziyi Yan ◽  
Helena Vihinen ◽  
Ove Eriksson ◽  
Weihuan Wang ◽  
...  
Keyword(s):  
Mitochondrial Function ◽  
Molecular Mechanisms ◽  
Membrane Curvature ◽  
Mitochondrial Morphology ◽  
Membrane Remodeling ◽  
Mitochondrial Ultrastructure ◽  
Bar Domain ◽  
Bar Domain Proteins ◽  
Domain Protein

Mitochondrial function is closely linked to its dynamic membrane ultrastructure. The mitochondrial inner membrane (MIM) can form extensive membrane invaginations known as cristae, which contain the respiratory chain and ATP synthase for oxidative phosphorylation. The molecular mechanisms regulating mitochondrial ultrastructure remain poorly understood. The Bin-Amphiphysin-Rvs (BAR) domain proteins are central regulators of diverse cellular processes related to membrane remodeling and dynamics. Whether BAR domain proteins are involved in sculpting membranes in specific submitochondrial compartments is largely unknown. In this study, we report FAM92A1 as a novel BAR domain protein localizes to the matrix side of the MIM. Loss of FAM92A1 caused a severe disruption to mitochondrial morphology and ultrastructure, impairing organelle bioenergetics. Furthermore, FAM92A1 displayed a membrane-remodeling activity in vitro, inducing a high degree of membrane curvature. Collectively, our findings uncover a role for a BAR domain protein as a critical organizer of the mitochondrial ultrastructure that is indispensable for mitochondrial function.

scholarly journals A putative N-BAR-domain protein is crucially required for the development of hyphae tip appressorium-like structure and its plant infection in Magnaporthe oryzae

2019 ◽  
Vol 1 (1) ◽  
Author(s):  
Lili Lin ◽  
Xiaomin Chen ◽  
Ammarah Shabbir ◽  
Si Chen ◽  
Xuewen Chen ◽  
...  
Keyword(s):  
Magnaporthe Oryzae ◽  
Lipid Membranes ◽  
Cellular Membrane ◽  
Gene Replacement ◽  
Bar Domain ◽  
Plant Infection ◽  
Expression Of Genes ◽  
Peripheral Proteins ◽  
Bar Domain Proteins ◽  
Replacement Technique

Abstract Membrane remodeling modulates many biological processes. The binding of peripheral proteins to lipid membranes results in membrane invaginations and protrusions, which regulate essential intra-cellular membrane and extra-cellular trafficking events. Proteins that bind and re-shape bio-membranes have been identified and extensively investigated. The Bin/Amphiphysin/Rvs (BAR) domain proteins are crescent-shape and play a conserved role in tubulation and sculpturing of cell membranes. We deployed targeted gene replacement technique to functionally characterize two hypothetical proteins (MoBar-A and MoBar-B) containing unitary N-BAR domain in Magnaporthe oryzae. The results obtained from phenotypic examinations showed that MoBAR-A deletion exerted a significant reduction in the growth of the defective ∆Mobar-A strain. Also, MoBAR-A disruption exclusively compromised hyphae-mediated infection. Additionally, the targeted replacement of MoBAR-A suppressed the expression of genes associated with the formation of hyphae tip appressorium-like structure in M. oryzae. Furthermore, single as well as combined deletion of MoBAR-A and MoBAR-B down-regulated the expression of nine different membrane-associated genes. From these results, we inferred that MoBAR-A plays a key and unique role in the pathogenesis of M. oryzae through direct or indirect regulation of the development of appressorium-like structures developed by hyphae tip. Taken together, these results provide unique insights into the direct contribution of the N-BAR domain proteins to morphological, reproduction, and infectious development of M. oryzae.

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