Regulation of the Actin Cytoskeleton-Plasma Membrane Interplay by Phosphoinositides

2010 ◽  
Vol 90 (1) ◽  
pp. 259-289 ◽  
Author(s):  
Juha Saarikangas ◽  
Hongxia Zhao ◽  
Pekka Lappalainen
Keyword(s):  
Plasma Membrane ◽  
Actin Cytoskeleton ◽  
Actin Dynamics ◽  
Actin Binding ◽  
Cell Physiology ◽  
Cortical Actin ◽  
Bar Domain ◽  
Pathogen Invasion ◽  
Associated Proteins ◽  
Continuous Dynamic

The plasma membrane and the underlying cortical actin cytoskeleton undergo continuous dynamic interplay that is responsible for many essential aspects of cell physiology. Polymerization of actin filaments against cellular membranes provides the force for a number of cellular processes such as migration, morphogenesis, and endocytosis. Plasma membrane phosphoinositides (especially phosphatidylinositol bis- and trisphosphates) play a central role in regulating the organization and dynamics of the actin cytoskeleton by acting as platforms for protein recruitment, by triggering signaling cascades, and by directly regulating the activities of actin-binding proteins. Furthermore, a number of actin-associated proteins, such as BAR domain proteins, are capable of directly deforming phosphoinositide-rich membranes to induce plasma membrane protrusions or invaginations. Recent studies have also provided evidence that the actin cytoskeleton-plasma membrane interactions are misregulated in a number of pathological conditions such as cancer and during pathogen invasion. Here, we summarize the wealth of knowledge on how the cortical actin cytoskeleton is regulated by phosphoinositides during various cell biological processes. We also discuss the mechanisms by which interplay between actin dynamics and certain membrane deforming proteins regulate the morphology of the plasma membrane.

scholarly journals Ultrastructure of the yeast actin cytoskeleton and its association with the plasma membrane.

1994 ◽  
Vol 125 (2) ◽  
pp. 381-391 ◽  
Author(s):  
J Mulholland ◽  
D Preuss ◽  
A Moon ◽  
A Wong ◽  
D Drubin ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Actin Cytoskeleton ◽  
Binding Proteins ◽  
Ultrastructural Level ◽  
Actin Binding ◽  
Cortical Actin ◽  
Actin Binding Proteins ◽  
Double Labeling ◽  
Wall Growth ◽  
Cortical Cytoskeleton

We characterized the yeast actin cytoskeleton at the ultrastructural level using immunoelectron microscopy. Anti-actin antibodies primarily labeled dense, patchlike cortical structures and cytoplasmic cables. This localization recapitulates results obtained with immunofluorescence light microscopy, but at much higher resolution. Immuno-EM double-labeling experiments were conducted with antibodies to actin together with antibodies to the actin binding proteins Abp1p and cofilin. As expected from immunofluorescence experiments, Abp1p, cofilin, and actin colocalized in immuno-EM to the dense patchlike structures but not to the cables. In this way, we can unambiguously identify the patches as the cortical actin cytoskeleton. The cortical actin patches were observed to be associated with the cell surface via an invagination of plasma membrane. This novel cortical cytoskeleton-plasma membrane interface appears to consist of a fingerlike invagination of plasma membrane around which actin filaments and actin binding proteins are organized. We propose a possible role for this unique cortical structure in wall growth and osmotic regulation.

scholarly journals Platelet adhesion: Structural and functional diversity of short dystrophin and utrophins in the formation of dystrophinassociated-protein complexes related to actin dynamics

2005 ◽  
Vol 94 (12) ◽  
pp. 1203-1212 ◽  
Author(s):  
Doris Cerecedo ◽  
Dalila Martínez-Rojas ◽  
Oscar Chávez ◽  
Francisco Martínez-Pérez ◽  
Francisco García-Sierra ◽  
...  
Keyword(s):  
Actin Cytoskeleton ◽  
Platelet Adhesion ◽  
Protein Complexes ◽  
Human Platelets ◽  
Actin Dynamics ◽  
Actin Binding ◽  
Dynamic Cell ◽  
Associated Proteins ◽  
Coated Surfaces ◽  
Dynamic Structures

SummaryPlatelets are dynamic cell fragments that modify their shape during activation. Utrophin and dystrophins are minor actin-binding proteins present in muscle and non-muscle cytoskeleton. In the present study, we characterised the pattern of Dp71 isoforms and utrophin gene products by immunoblot in human platelets. Two new dystrophin isoforms were found, Dp71f and Dp71d, as well as the Up71 isoform and the dystrophin-associated proteins, α and β-dystrobrevins. Distribution of Dp71d/Dp71Δ110 m, Up400/Up71 and dystrophin-associated proteins in relation to the actin cytoskeleton was evaluated by confocal microscopy in both resting and platelets adhered on glass. Formation of two dystrophin-associated protein complexes (Dp71d/Dp71Δ110 m ~DAPC and Up400/Up71~DAPC) was demonstrated by co-immunoprecipitation and their distribution in relation to the actin cytoskeleton was characterised during platelet adhesion. The Dp71d/Dp71Δ110 m ~DAPC is maintained mainly at the granulomere and is associated with dynamic structures during activation by adhesion to thrombin-coated surfaces. Participation of both Dp71d/Dp71Δ110 m ~DAPC and Up400/Up71~DAPC in the biological roles of the platelets is discussed.

scholarly journals The BAR domain of the Arf GTPase-activating protein ASAP1 directly binds actin filaments

2020 ◽  
Vol 295 (32) ◽  
pp. 11303-11315
Author(s):  
Pei-Wen Chen ◽  
Neil Billington ◽  
Ben Y. Maron ◽  
Jeffrey A. Sload ◽  
Krishna Chinthalapudi ◽  
...  
Keyword(s):  
Actin Cytoskeleton ◽  
Protein Interactions ◽  
Actin Filaments ◽  
Focal Adhesions ◽  
Actin Dynamics ◽  
Ph Domain ◽  
Gtpase Activating Protein ◽  
Cortical Actin ◽  
Bar Domain ◽  
Spontaneous Polymerization

The Arf GTPase-activating protein (Arf GAP) with SH3 domain, ankyrin repeat and PH domain 1 (ASAP1) establishes a connection between the cell membrane and the cortical actin cytoskeleton. The formation, maintenance, and turnover of actin filaments and bundles in the actin cortex are important for cell adhesion, invasion, and migration. Here, using actin cosedimentation, polymerization, and depolymerization assays, along with total internal reflection fluorescence (TIRF), confocal, and EM analyses, we show that the N-terminal N-BAR domain of ASAP1 directly binds to F-actin. We found that ASAP1 homodimerization aligns F-actin in predominantly unipolar bundles and stabilizes them against depolymerization. Furthermore, the ASAP1 N-BAR domain moderately reduced the spontaneous polymerization of G-actin. The overexpression of the ASAP1 BAR–PH tandem domain in fibroblasts induced the formation of actin-filled projections more effectively than did full-length ASAP1. An ASAP1 construct that lacked the N-BAR domain failed to induce cellular projections. Our results suggest that ASAP1 regulates the dynamics and the formation of higher-order actin structures, possibly through direct binding to F-actin via its N-BAR domain. We propose that ASAP1 is a hub protein for dynamic protein–protein interactions in mechanosensitive structures, such as focal adhesions, invadopodia, and podosomes, that are directly implicated in oncogenic events. The effect of ASAP1 on actin dynamics puts a spotlight on its function as a central signaling molecule that regulates the dynamics of the actin cytoskeleton by transmitting signals from the plasma membrane.

scholarly journals The Saccharomyces cerevisiae Calponin/Transgelin Homolog Scp1 Functions with Fimbrin to Regulate Stability and Organization of the Actin Cytoskeleton

2003 ◽  
Vol 14 (7) ◽  
pp. 2617-2629 ◽  
Author(s):  
Anya Goodman ◽  
Bruce L. Goode ◽  
Paul Matsudaira ◽  
Gerald R. Fink
Keyword(s):  
Actin Cytoskeleton ◽  
Actin Binding ◽  
Filamentous Actin ◽  
Cortical Actin ◽  
Associated Proteins ◽  
Cross Links ◽  
Biochemical Analyses ◽  
Actin Patch ◽  
The One

Calponins and transgelins are members of a conserved family of actin-associated proteins widely expressed from yeast to humans. Although a role for calponin in muscle cells has been described, the biochemical activities and in vivo functions of nonmuscle calponins and transgelins are largely unknown. Herein, we have used genetic and biochemical analyses to characterize the budding yeast member of this family, Scp1, which most closely resembles transgelin and contains one calponin homology (CH) domain. We show that Scp1 is a novel component of yeast cortical actin patches and shares in vivo functions and biochemical activities with Sac6/fimbrin, the one other actin patch component that contains CH domains. Purified Scp1 binds directly to filamentous actin, cross-links actin filaments, and stabilizes filaments against disassembly. Sequences in Scp1 sufficient for actin binding and cross-linking reside in its carboxy terminus, outside the CH domain. Overexpression of SCP1 suppresses sac6Δ defects, and deletion of SCP1 enhances sac6Δ defects. Together, these data show that Scp1 and Sac6/fimbrin cooperate to stabilize and organize the yeast actin cytoskeleton.

scholarly journals α-Catenin–mediated cadherin clustering couples cadherin and actin dynamics

2015 ◽  
Vol 210 (4) ◽  
pp. 647-661 ◽  
Author(s):  
Chi-Shuo Chen ◽  
Soonjin Hong ◽  
Indrajyoti Indra ◽  
Alina P. Sergeeva ◽  
Regina B. Troyanovsky ◽  
...  
Keyword(s):  
Actin Cytoskeleton ◽  
Molecular Mechanism ◽  
Point Mutations ◽  
Actin Dynamics ◽  
Actin Binding ◽  
Cortical Actin ◽  
Actin Binding Domain ◽  
Cell Adhesive ◽  
Cis And Trans

The function of the actin-binding domain of α-catenin, αABD, including its possible role in the direct anchorage of the cadherin–catenin complex to the actin cytoskeleton, has remained uncertain. We identified two point mutations on the αABD surface that interfere with αABD binding to actin and used them to probe the role of α-catenin–actin interactions in adherens junctions. We found that the junctions directly bound to actin via αABD were more dynamic than the junctions bound to actin indirectly through vinculin and that recombinant αABD interacted with cortical actin but not with actin bundles. This interaction resulted in the formation of numerous short-lived cortex-bound αABD clusters. Our data suggest that αABD clustering drives the continuous assembly of transient, actin-associated cadherin–catenin clusters whose disassembly is maintained by actin depolymerization. It appears then that such actin-dependent αABD clustering is a unique molecular mechanism mediating both integrity and reassembly of the cell–cell adhesive interface formed through weak cis- and trans-intercadherin interactions.

scholarly journals VASP mediated actin dynamics activate and recruit a filopodia myosin

2021 ◽  
Author(s):  
Ashley L Arthur ◽  
Amy Crawford ◽  
Anne Houdusse ◽  
Margaret A Titus
Keyword(s):  
Actin Cytoskeleton ◽  
Actin Polymerization ◽  
The State ◽  
Actin Dynamics ◽  
Actin Binding ◽  
Actin Network ◽  
Cortical Actin ◽  
Close Collaboration ◽  
Actin Binding Protein ◽  
Dynamic Regions

Filopodia are thin, actin-based structures that cells use to interact with their environments. Filopodia initiation requires a suite of conserved proteins but the mechanism remains poorly understood. The actin polymerase VASP and a MyTH-FERM (MF) myosin, DdMyo7 in amoeba, are essential for filopodia initiation. DdMyo7 is localized to dynamic regions of the actin-rich cortex. Analysis of VASP mutants and treatment of cells with anti-actin drugs shows that myosin recruitment and activation in Dictyostelium requires localized VASP-dependent actin polymerization. Targeting of DdMyo7 to the cortex alone is not sufficient for filopodia initiation; VASP activity is also required. The actin regulator locally produces a cortical actin network, that activates the MF myosin and together they shape the actin network to promote extension of parallel bundles during filopodia formation. This work reveals how filopodia initiation requires close collaboration between an actin binding protein, the state of the actin cytoskeleton and MF myosin activity.

scholarly journals VASP mediated actin dynamics activate and recruit a filopodia myosin

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Ashley L Arthur ◽  
Amy Crawford ◽  
Anne Houdusse ◽  
Margaret A Titus
Keyword(s):  
Actin Cytoskeleton ◽  
Actin Polymerization ◽  
The State ◽  
Actin Dynamics ◽  
Actin Binding ◽  
Actin Network ◽  
Cortical Actin ◽  
Close Collaboration ◽  
Actin Binding Protein ◽  
Dynamic Regions

Filopodia are thin, actin-based structures that cells use to interact with their environments. Filopodia initiation requires a suite of conserved proteins but the mechanism remains poorly understood. The actin polymerase VASP and a MyTH-FERM (MF) myosin, DdMyo7 in amoeba, are essential for filopodia initiation. DdMyo7 is localized to dynamic regions of the actin-rich cortex. Analysis of VASP mutants and treatment of cells with anti-actin drugs shows that myosin recruitment and activation in Dictyostelium requires localized VASP-dependent actin polymerization. Targeting of DdMyo7 to the cortex alone is not sufficient for filopodia initiation; VASP activity is also required. The actin regulator locally produces a cortical actin network that activates myosin and together they shape the actin network to promote extension of parallel bundles of actin during filopodia formation. This work reveals how filopodia initiation requires close collaboration between an actin binding protein, the state of the actin cytoskeleton and MF myosin activity.

scholarly journals Sla2p Is Associated with the Yeast Cortical Actin Cytoskeleton via Redundant Localization Signals

1999 ◽  
Vol 10 (7) ◽  
pp. 2265-2283 ◽  
Author(s):  
Shirley Yang ◽  
M. Jamie T. V. Cope ◽  
David G. Drubin
Keyword(s):  
Plasma Membrane ◽  
Actin Cytoskeleton ◽  
Coiled Coil ◽  
Intramolecular Interactions ◽  
The Other ◽  
Actin Binding ◽  
Filamentous Actin ◽  
Cortical Actin ◽  
C Terminus

Sla2p, also known as End4p and Mop2p, is the founding member of a widely conserved family of actin-binding proteins, a distinguishing feature of which is a C-terminal region homologous to the C terminus of talin. These proteins may function in actin cytoskeleton-mediated plasma membrane remodeling. A human homologue of Sla2p binds to huntingtin, the protein whose mutation results in Huntington’s disease. Here we establish by immunolocalization that Sla2p is a component of the yeast cortical actin cytoskeleton. Deletion analysis showed that Sla2p contains two separable regions, which can mediate association with the cortical actin cytoskeleton, and which can provide Sla2p function. One localization signal is actin based, whereas the other signal is independent of filamentous actin. Biochemical analysis showed that Sla2p exists as a dimer in vivo. Two-hybrid analysis revealed two intramolecular interactions mediated by coiled-coil domains. One of these interactions appears to underlie dimer formation. The other appears to contribute to the regulation of Sla2p distribution between the cytoplasm and plasma membrane. The data presented are used to develop a model for Sla2p regulation and interactions.

scholarly journals Specific release of membrane-bound annexin II and cortical cytoskeletal elements by sequestration of membrane cholesterol.

1997 ◽  
Vol 8 (3) ◽  
pp. 533-545 ◽  
Author(s):  
T Harder ◽  
R Kellner ◽  
R G Parton ◽  
J Gruenberg
Keyword(s):  
Actin Cytoskeleton ◽  
Cytoskeletal Proteins ◽  
Annexin Ii ◽  
Dependent Manner ◽  
Cortical Actin ◽  
Independent Manner ◽  
Low Concentrations ◽  
Early Endosomes ◽  
Associated Proteins ◽  
Cytoskeletal Elements

Annexin II is an abundant protein which is present in the cytosol and on the cytoplasmic face of plasma membrane and early endosomes. It is generally believed that this association occurs via Ca(2+)-dependent binding to lipids, a mechanism typical for the annexin protein family. Although previous studies have shown that annexin II is involved in early endosome dynamics and organization, the precise biological role of the protein is unknown. In this study, we found that approximately 50% of the total cellular annexin was associated with membranes in a Ca(2+)-independent manner. This binding was extremely tight, since it resisted high salt and, to some extent, high pH treatments. We found, however, that membrane-associated annexin II could be quantitatively released by low concentrations of the cholesterol-sequestering agents filipin and digitonin. Both treatments released an identical and limited set of proteins but had no effects on other membrane-associated proteins. Among the released proteins, we identified, in addition to annexin II itself, the cortical cytoskeletal proteins alpha-actinin, ezrin and moesin, and membrane-associated actin. Our biochemical and immunological observations indicate that these proteins are part of a complex containing annexin II and that stability of the complex is sensitive to cholesterol sequestering agents. Since annexin II is tightly membrane-associated in a cholesterol-dependent manner, and since it seems to interact physically with elements of the cortical actin cytoskeleton, we propose that the protein serves as interface between membranes containing high amounts of cholesterol and the actin cytoskeleton.

scholarly journals Synthetic lethality screen identifies a novel yeast myosin I gene (MYO5): myosin I proteins are required for polarization of the actin cytoskeleton.

1996 ◽  
Vol 133 (6) ◽  
pp. 1277-1291 ◽  
Author(s):  
H V Goodson ◽  
B L Anderson ◽  
H M Warrick ◽  
L A Pon ◽  
J A Spudich
Keyword(s):  
Actin Cytoskeleton ◽  
Synthetic Lethality ◽  
Critical Role ◽  
Neck Region ◽  
Actin Binding ◽  
Cell Physiology ◽  
Deletion Mutants ◽  
Tail Domain ◽  
Amino Terminal ◽  
Myosin I

The organization of the actin cytoskeleton plays a critical role in cell physiology in motile and nonmotile organisms. Nonetheless, the function of the actin based motor molecules, members of the myosin superfamily, is not well understood. Deletion of MYO3, a yeast gene encoding a "classic" myosin I, has no detectable phenotype. We used a synthetic lethality screen to uncover genes whose functions might overlap with those of MYO3 and identified a second yeast myosin 1 gene, MYO5. MYO5 shows 86 and 62% identity to MYO3 across the motor and non-motor regions. Both genes contain an amino terminal motor domain, a neck region containing two IQ motifs, and a tail domain consisting of a positively charged region, a proline-rich region containing sequences implicated in ATP-insensitive actin binding, and an SH3 domain. Although myo5 deletion mutants have no detectable phenotype, yeast strains deleted for both MYO3 and MYO5 have severe defects in growth and actin cytoskeletal organization. Double deletion mutants also display phenotypes associated with actin disorganization including accumulation of intracellular membranes and vesicles, cell rounding, random bud site selection, sensitivity to high osmotic strength, and low pH as well as defects in chitin and cell wall deposition, invertase secretion, and fluid phase endocytosis. Indirect immunofluorescence studies using epitope-tagged Myo5p indicate that Myo5p is localized at actin patches. These results indicate that MYO3 and MYO5 encode classical myosin I proteins with overlapping functions and suggest a role for Myo3p and Myo5p in organization of the actin cytoskeleton of Saccharomyces cerevisiae.

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