The Bin/Amphiphysin/Rvs (BAR) Domain Protein Endophilin B2 Interacts with Plectin and Controls Perinuclear Cytoskeletal Architecture

Proteins of the Bin/amphiphysin/Rvs (BAR) domain superfamily are essential in controlling the shape and dynamics of intracellular membranes. Here, we present evidence for the unconventional function of a member of the endophilin family of BAR and Src homology 3 domain-containing proteins, namely endophilin B2, in the perinuclear organization of intermediate filaments. Using mass spectrometry analysis based on capturing endophilin B2 partners in in situ pre-established complexes in cells, we unravel the interaction of endophilin B2 with plectin 1, a variant of the cytoskeleton linker protein plectin as well as with vimentin. Endophilin B2 directly binds the N-terminal region of plectin 1 via Src homology 3-mediated interaction and vimentin indirectly via plectin-mediated interaction. The relevance of these interactions is strengthened by the selective and drastic reorganization of vimentin around nuclei upon overexpression of endophilin B2 and by the extensive colocalization of both proteins in a meshwork of perinuclear filamentous structures. By generating mutants of the endophilin B2 BAR domain, we show that this phenotype requires the BAR-mediated membrane binding activity of endophilin B2. Plectin 1 or endophilin B2 knockdown using RNA interference disturbed the perinuclear organization of vimentin. Altogether, these data suggest that the endophilin B2-plectin 1 complex functions as a membrane-anchoring device organizing and stabilizing the perinuclear network of vimentin filaments. Finally, we present evidence for the involvement of endophilin B2 and plectin 1 in nuclear positioning in individual cells. This points to the potential importance of the endophilin B2-plectin complex in the biological functions depending on nuclear migration and positioning.

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Faculty Opinions recommendation of The Src homology 3 domain of the beta-subunit of voltage-gated calcium channels promotes endocytosis via dynamin interaction.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1064854.517791 ◽

2007 ◽

Author(s):

Brett Adams

Keyword(s):

Calcium Channels ◽

Beta Subunit ◽

Voltage Gated ◽

Src Homology 3 ◽

Voltage Gated Calcium Channels ◽

Src Homology 3 Domain ◽

Src Homology

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Faculty Opinions recommendation of Identification of a link between the SAMP repeats of adenomatous polyposis coli tumor suppressor and the Src homology 3 domain of DDEF.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1141847.598934 ◽

2009 ◽

Author(s):

Chloe Bulinski ◽

Andy Tran

Keyword(s):

Tumor Suppressor ◽

Adenomatous Polyposis Coli ◽

Adenomatous Polyposis ◽

Polyposis Coli ◽

Src Homology 3 ◽

Src Homology 3 Domain ◽

Src Homology

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MyelStones: the executive roles of myelin basic protein in myelin assembly and destabilization in multiple sclerosis

Biochemical Journal ◽

10.1042/bj20150710 ◽

2015 ◽

Vol 472 (1) ◽

pp. 17-32 ◽

Cited By ~ 44

Author(s):

Kenrick A. Vassall ◽

Vladimir V. Bamm ◽

George Harauz

Keyword(s):

Multiple Sclerosis ◽

Myelin Basic Protein ◽

Intrinsically Disordered Proteins ◽

Basic Protein ◽

Disordered Proteins ◽

Post Translational Modifications ◽

Src Homology 3 ◽

Intrinsically Disordered ◽

Src Homology ◽

Membrane Anchoring

The classic isoforms of myelin basic protein (MBP, 14–21.5 kDa) are essential to formation of the multilamellar myelin sheath of the mammalian central nervous system (CNS). The predominant 18.5-kDa isoform links together the cytosolic surfaces of oligodendrocytes, but additionally participates in cytoskeletal turnover and membrane extension, Fyn-mediated signalling pathways, sequestration of phosphoinositides and maintenance of calcium homoeostasis. All MBP isoforms are intrinsically disordered proteins (IDPs) that interact via molecular recognition fragments (MoRFs), which thereby undergo local disorder-to-order transitions. Their conformations and associations are modulated by environment and by a dynamic barcode of post-translational modifications, particularly phosphorylation by mitogen-activated and other protein kinases and deimination [a hallmark of demyelination in multiple sclerosis (MS)]. The MBPs are thus to myelin what basic histones are to chromatin. Originally thought to be merely structural proteins forming an inert spool, histones are now known to be dynamic entities involved in epigenetic regulation and diseases such as cancer. Analogously, the MBPs are not mere adhesives of compact myelin, but active participants in oligodendrocyte proliferation and in membrane process extension and stabilization during myelinogenesis. A central segment of these proteins is pivotal in membrane-anchoring and SH3 domain (Src homology 3) interaction. We discuss in the present review advances in our understanding of conformational conversions of this classic basic protein upon membrane association, including new thermodynamic analyses of transitions into different structural ensembles and how a shift in the pattern of its post-translational modifications is associated with the pathogenesis and potentially onset of demyelination in MS.

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Four proline-rich sequences of the guanine-nucleotide exchange factor C3G bind with unique specificity to the first Src homology 3 domain of Crk

Journal of Biological Chemistry ◽

10.1016/s0021-9258(20)30059-4 ◽

1994 ◽

Vol 269 (52) ◽

pp. 32781-32787

Author(s):

B S Knudsen ◽

S M Feller ◽

H Hanafusa

Keyword(s):

Guanine Nucleotide Exchange Factor ◽

Guanine Nucleotide ◽

Nucleotide Exchange ◽

Exchange Factor ◽

Src Homology 3 ◽

Guanine Nucleotide Exchange ◽

Nucleotide Exchange Factor ◽

Src Homology 3 Domain ◽

Src Homology ◽

Unique Specificity

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Myosin 1E coordinates actin assembly and cargo trafficking during clathrin-mediated endocytosis

Molecular Biology of the Cell ◽

10.1091/mbc.e11-04-0383 ◽

2012 ◽

Vol 23 (15) ◽

pp. 2891-2904 ◽

Cited By ~ 57

Author(s):

Jackie Cheng ◽

Alexandre Grassart ◽

David G. Drubin

Keyword(s):

Mammalian Cells ◽

Actin Polymerization ◽

Type I ◽

Actin Assembly ◽

Significant Delay ◽

Src Homology 3 ◽

Integral Role ◽

Src Homology 3 Domain ◽

Src Homology ◽

Endocytic Vesicles

Myosin 1E (Myo1E) is recruited to sites of clathrin-mediated endocytosis coincident with a burst of actin assembly. The recruitment dynamics and lifetime of Myo1E are similar to those of tagged actin polymerization regulatory proteins. Like inhibition of actin assembly, depletion of Myo1E causes reduced transferrin endocytosis and a significant delay in transferrin trafficking to perinuclear compartments, demonstrating an integral role for Myo1E in these actin-mediated steps. Mistargeting of GFP-Myo1E or its src-homology 3 domain to mitochondria results in appearance of WIP, WIRE, N-WASP, and actin filaments at the mitochondria, providing evidence for Myo1E's role in actin assembly regulation. These results suggest for mammalian cells, similar to budding yeast, interdependence in the recruitment of type I myosins, WIP/WIRE, and N-WASP to endocytic sites for Arp2/3 complex activation to assemble F-actin as endocytic vesicles are being formed.

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Phosphorylation of BACH1 switches its function from transcription factor to mitotic chromosome regulator and promotes its interaction with HMMR

Biochemical Journal ◽

10.1042/bcj20170520 ◽

2018 ◽

Vol 475 (5) ◽

pp. 981-1002 ◽

Cited By ~ 9

Author(s):

Jie Li ◽

Hiroki Shima ◽

Hironari Nishizawa ◽

Masatoshi Ikeda ◽

Andrey Brydun ◽

...

Keyword(s):

Mitotic Spindle ◽

Isotope Labeling ◽

Binding Activity ◽

Mass Spectrometry Analysis ◽

Spindle Orientation ◽

Mitotic Spindles ◽

Spectrometry Analysis ◽

Dna Binding Activity ◽

Ejection Force ◽

M Phase

The transcription repressor BACH1 performs mutually independent dual roles in transcription regulation and chromosome alignment during mitosis by supporting polar ejection force of mitotic spindle. We now found that the mitotic spindles became oblique relative to the adhesion surface following endogenous BACH1 depletion in HeLa cells. This spindle orientation rearrangement was rescued by re-expression of BACH1 depending on its interactions with HMMR and CRM1, both of which are required for the positioning of mitotic spindle, but independently of its DNA-binding activity. A mass spectrometry analysis of BACH1 complexes in interphase and M phase revealed that BACH1 lost during mitosis interactions with proteins involved in chromatin and gene expression but retained interactions with HMMR and its known partners including CHICA. By analyzing BACH1 modification using stable isotope labeling with amino acids in cell culture, mitosis-specific phosphorylations of BACH1 were observed, and mutations of these residues abolished the activity of BACH1 to restore mitotic spindle orientation in knockdown cells and to interact with HMMR. Detailed histological analysis of Bach1-deficient mice revealed lengthening of the epithelial fold structures of the intestine. These observations suggest that BACH1 performs stabilization of mitotic spindle orientation together with HMMR and CRM1 in mitosis, and that the cell cycle-specific phosphorylation switches the transcriptional and mitotic functions of BACH1.

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