GMF as an Actin Network Remodeling Factor

Goode, Bruce L.; Sweeney, Meredith O.; Eskin, Julian A.

doi:10.1016/j.tcb.2018.04.008

Cited by 29 publications

(30 citation statements)

References 98 publications

(164 reference statements)

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“…Interestingly, NC1‐peptide overexpression in the testis also downregulated PCP protein Dvl3, but not Fzd3 and Prickle 1 (Figure A,B). Furthermore, NC1‐peptide overexpression downregulated actin nucleation proteins Spire 1 and formin 1, actin barbed end capping and bundling protein Eps8, but a mild and persistent upregulation of Arp3 was noted (Figure A,B), wherein Arp3 together with Arp2 create the Arp2/3 complex which is known to induce branched actin polymerization, converting bundled actin filaments into a branched network, thereby destabilizing the F‐actin network …”

Section: Resultsmentioning

confidence: 99%

NC1‐peptide regulates spermatogenesis through changes in cytoskeletal organization mediated by EB1

Liu

et al. 2020

FASEB j.

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are contributed equally to the completion of this work.Abbreviations: +TIP, microtubule plus (+)-end tracking protein; AJ, adherens junction; aPKC, atypical protein kinase C; Arp3, actin-related protein 3; BM, basement membrane; BTB, blood-testis barrier; Crb3, Crumbs homolog-3; DAPI, 4', 6-diamidino-2-phenylindole; Dia1, Diaphanous-related formin-1; Dlg1, Discs large 1; Dvl3, Disheveled 3; EB1, end-binding protein 1; Eps8, epidermal growth factor receptor pathway substrate 8; ES, ectoplasmic specialization; Fzd3, Frizzled 3; F12/DMEM, Ham's F12 nutrient mixture/Dulbecco's modified Eagle's medium (1:1, vol/vol); GAPDH, glyceraldehyde 3-phosphate dehydrogenase; GJ, gap junction; H&E, hematoxylin and eosin staining; IF, immunofluorescence microscopy; IgG, immunoglobulin; IP, immunoprecipitation; MAP1a, microtubule-associated protein 1a; MARK, microtubule affinity-regulatory kinase 4; MT, microtubule; mTOR, mammalian target of rapamycin; NC1 domain, non-collagenous domain 1; Pals1, protein associated with Lin-7 1; PatJ, Pals1-associated tight junction protein; Par6, partitioning-defective (Par) protein 6; rpS6, ribosomal protein S6; TJ, tight junction; ZO-1, zonula occludens-1. AbstractDuring the epithelial cycle of spermatogenesis, different sets of cellular events take place across the seminiferous epithelium in the testis. For instance, remodeling of the blood-testis barrier (BTB) that facilitates the transport of preleptotene spermatocytes across the immunological barrier and the release of sperms at spermiation take place at the opposite ends of the epithelium simultaneously at stage VIII of the epithelial cycle. These cellular events are tightly coordinated via locally produced regulatory biomolecules. Studies have shown that collagen α3 (IV) chains, a major constituent component of the basement membrane, release the non-collagenous (NC) 1 domain, a 28-kDa peptide, designated NC1-peptide, from the C-terminal region, via the action of MMP-9 (matrix metalloproteinase 9). NC1-peptide was found to be capable of inducing BTB remodeling and spermatid release across the epithelium. As such, the NC1-peptide is an endogenously produced biologically active peptide which coordinates these cellular events across the epithelium in stage VIII tubules. Herein, we used an animal model, wherein NC1-peptide cloned into the pCI-neo mammalian expression vector was overexpressed in the testis, to better understanding the molecular mechanism by which NC1-peptide regulated spermatogenic function. It was shown that NC1-peptide induced considerable downregulation on a number of cell polarity and planar cell polarity (PCP) proteins, and studies have shown these polarity and PCP proteins modulate spermatid polarity and adhesion via their effects on microtubule (MT) and F-actin cytoskeletal organization across the epithelium. More important, NC1-peptide exerted its effects by downregulating the expression of microtubule (MT) plus-end tracking protein (+TIP) called EB1 (end-binding protein 1). We cloned the full-length EB1 cDNA for its ov...

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Section: Resultsmentioning

confidence: 99%

NC1‐peptide regulates spermatogenesis through changes in cytoskeletal organization mediated by EB1

Liu

et al. 2020

FASEB j.

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“…Force Promotes but BeF x Inhibits Debranching by GMF. GMF (20)(21)(22) promotes the dissociation of actin filament branches without applied force, so we measured how the concentration of fission yeast GMF influences the rates of dissociation of actin filament branches with ADP−BeF x −Arp2/3 complex or ADP−Arp2/3 complex at a low buffer flow rate (15 μL•min −1 ). This flow rate exerts very little force on branches and had little or no effect on debranching (Fig.…”

Section: The Nucleotide State Of the Actin Filaments Does Not Influencementioning

confidence: 99%

“…4, so its value differs depending on how the data are plotted. Reported affinities of GMF for soluble Arp2/3 complex (K d,GMF ) vary widely: >>10 μM for ATP−Arp 2/3 complex (43); 0.7 μM for ADP−Arp2/3 complex (43); and 13 nM (20)(21)(22) or ∼1 μM (44) for Arp2/3 complex without a specified nucleotide. We found that the measured affinity of GMF for Arp2/3 complex in branch junctions bound to both a mother and daughter filament depended on the bound nucleotide.…”

Section: Implications Of the Force Sensitivity Of Branches For Their mentioning

confidence: 99%

“…Networks of branched actin filaments turn over much more rapidly in cells than in vitro when assembled from purified proteins (16)(17)(18)(19). The regulatory proteins cofilin and glia maturation factor (GMF) accelerate debranching and have been implicated in accelerating branched network remodeling and turnover (20)(21)(22)(23)(24). Although not investigated previously, mechanical forces may also affect network disassembly through debranching.…”

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confidence: 99%

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Force and phosphate release from Arp2/3 complex promote dissociation of actin filament branches

Pandit

Cao

Bibeau

et al. 2020

Proc. Natl. Acad. Sci. U.S.A.

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Networks of branched actin filaments formed by Arp2/3 complex generate and experience mechanical forces during essential cellular functions, including cell motility and endocytosis. External forces regulate the assembly and architecture of branched actin networks both in vitro and in cells. Considerably less is known about how mechanical forces influence the disassembly of actin filament networks, specifically, the dissociation of branches. We used microfluidics to apply force to branches formed from purified muscle actin and fission yeast Arp2/3 complex and observed debranching events in real time with total internal reflection fluorescence microscopy. Low forces in the range of 0 pN to 2 pN on branches accelerated their dissociation from mother filaments more than two orders of magnitude, from hours to <1 min. Neither force on the mother filament nor thermal fluctuations in mother filament shape influenced debranching. Arp2/3 complex at branch junctions adopts two distinct mechanical states with different sensitivities to force, which we name “young/strong” and “old/weak.” The “young/strong” state 1 has adenosine 5′-diphosphate (ADP)−Pibound to Arp2/3 complex. Phosphate release converts Arp2/3 complex into the “old/weak” state 2 with bound ADP, which is 20 times more sensitive to force than state 1. Branches with ADP−Arp2/3 complex are more sensitive to debranching by fission yeast GMF (glia maturation factor) than branches with ADP−Pi−Arp2/3 complex. These findings suggest that aging of branch junctions by phosphate release from Arp2/3 complex and mechanical forces contribute to disassembling “old” actin filament branches in cells.

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“…Although WRC/Arp2/3 complex-dependent branching is agreed to be indispensable for initiation and maintenance of this structure [6], the functions of additional players in the family of actin assembly factors are just beginning to emerge [57,67,68], including the relevance of profilin, profilin-bound actin and the precise nature in distinct tissues and cell types of the "re-charging" activity of ADP-actin monomers with ATP [78]. Moreover, we have refrained from emphasizing the relevance of coronin and members of the actin depolymerizing factor homology (ADF-H) family, including GMF, which have been excellently covered in recent reviews [92,93]. Notably, the relative relevance of all these factors in actin network remodelling and/or disassembly remains to be established.…”

Section: Conclusion and Future Perspectivesmentioning

confidence: 99%

Assembling actin filaments for protrusion

Rottner

Schaks

2019

Current Opinion in Cell Biology

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Cell migration entails a plethora of activities combining the productive exertion of protrusive and contractile forces to allow cells to push and squeeze themselves through cell clumps, interstitial tissues or tissue borders. All these activities require the generation and turnover of actin filaments that arrange into specific, subcellular structures. The most prominent structures mediating the protrusion at the leading edges of cells include lamellipodia and filopodia as well as plasma membrane blebs. Moreover, in cells migrating on planar substratum, mechanical support is being provided by an additional, more proximally located structure termed the lamella. Here, we systematically dissect the literature concerning the mechanisms driving actin filament nucleation and elongation in the best-studied protrusive structure, the lamellipodium. Recent work has shed light on open questions in lamellipodium protrusion, including the relative contributions of nucleation versus elongation to the assembly of both individual filaments and the lamellipodial network as a whole. However, much remains to be learned concerning the specificity and relevance of individual factors, their cooperation and their site-specific functions relative to the importance of global actin monomer and filament homeostasis.

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GMF as an Actin Network Remodeling Factor

Cited by 29 publications

References 98 publications

NC1‐peptide regulates spermatogenesis through changes in cytoskeletal organization mediated by EB1

NC1‐peptide regulates spermatogenesis through changes in cytoskeletal organization mediated by EB1

Force and phosphate release from Arp2/3 complex promote dissociation of actin filament branches

Assembling actin filaments for protrusion

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