scholarly journals CARMIL3 is important for cell migration and morphogenesis during early development in zebrafish

2020 ◽  
Author(s):  
Benjamin C. Stark ◽  
Yuanyuan Gao ◽  
Lakyn Belk ◽  
Matthew A. Culver ◽  
Bo Hu ◽  
...  
Keyword(s):  
Cell Migration ◽  
Cluster Formation ◽  
Actin Assembly ◽  
Capping Protein ◽  
Capping Proteins ◽  
Myosin I ◽  
Actin Capping Protein ◽  
Endodermal Cells ◽  
Actin Capping

AbstractCell migration is important during early animal embryogenesis. Cell migration and cell shape are controlled by actin assembly and dynamics, which depend on capping proteins, including the barbed-end heterodimeric actin capping protein (CP). CP activity can be regulated by capping-protein-interacting (CPI) motif proteins, including CARMIL (capping protein Arp2/3 myosin-I linker) family proteins. Previous studies of CARMIL3, one of the three highly conserved CARMIL genes in vertebrates, have largely been limited to cells in culture. Towards understanding CARMIL function during embryogenesis in vivo, we analyzed zebrafish lines carrying mutations of carmil3. Maternal-zygotic mutants show impaired endodermal migration during gastrulation, along with defects in dorsal forerunner cell (DFC) cluster formation, affecting the morphogenesis of Kupffer’s vesicle (KV). Mutant KVs are smaller and display decreased numbers of cilia, leading to defects in left/right (L/R) patterning with variable penetrance and expressivity. The penetrance and expressivity of the KV phenotype in carmil3 mutants correlated well with the L/R heart positioning defect at the end of embryogenesis. This first in vivo animal study of CARMIL3 reveals its new role for CARMIL3 during morphogenesis of the vertebrate embryo. This role involves migration of endodermal cells and DFCs, along with subsequent morphogenesis of the KV and L/R asymmetry.

scholarly journals Vertebrate Isoforms of Actin Capping Protein β Have Distinct Functions in Vivo

1999 ◽  
Vol 147 (6) ◽  
pp. 1287-1298 ◽  
Author(s):  
Marilyn C. Hart ◽  
John A. Cooper
Keyword(s):  
Actin Filaments ◽  
Cell Periphery ◽  
Actin Assembly ◽  
Severe Phenotype ◽  
Intercalated Disc ◽  
Capping Protein ◽  
Intercalated Discs ◽  
Actin Capping Protein ◽  
Actin Capping

Actin capping protein (CP) binds barbed ends of actin filaments to regulate actin assembly. CP is an α/β heterodimer. Vertebrates have conserved isoforms of each subunit. Muscle cells contain two β isoforms. β1 is at the Z-line; β2 is at the intercalated disc and cell periphery in general. To investigate the functions of the isoforms, we replaced one isoform with another using expression in hearts of transgenic mice. Mice expressing β2 had a severe phenotype with juvenile lethality. Myofibril architecture was severely disrupted. The β2 did not localize to the Z-line. Therefore, β1 has a distinct function that includes interactions at the Z-line. Mice expressing β1 showed altered morphology of the intercalated disc, without the lethality or myofibril disruption of the β2-expressing mice. The in vivo function of CP is presumed to involve binding barbed ends of actin filaments. To test this hypothesis, we expressed a β1 mutant that poorly binds actin. These mice showed both myofibril disruption and intercalated disc remodeling, as predicted. Therefore, CPβ1 and CPβ2 each have a distinct function that cannot be provided by the other isoform. CPβ1 attaches actin filaments to the Z-line, and CPβ2 organizes the actin at the intercalated discs.

scholarly journals The dynein light chain protein Tda2 functions as a dimerization engine to regulate actin capping protein during endocytosis

2021 ◽  
pp. mbc.E21-01-0032
Author(s):  
Andrew K. Lamb ◽  
Andres N. Fernandez ◽  
Olve B. Peersen ◽  
Santiago M. Di Pietro
Keyword(s):  
Light Chain ◽  
Mammalian Cells ◽  
Dynein Light Chain ◽  
Actin Assembly ◽  
Filamentous Actin ◽  
Capping Protein ◽  
Actin Capping Protein ◽  
Actin Capping ◽  
Protein Recruitment

Clathrin- and actin-mediated endocytosis is a fundamental process in eukaryotic cells. Previously, we discovered Tda2 as a new yeast dynein light chain that works with Aim21 to regulate actin assembly during endocytosis. Here, we show Tda2 functions as a dimerization engine bringing two Aim21 molecules together using a novel binding surface different than the canonical dynein light chain ligand binding groove. Point mutations on either protein that diminish the Tda2-Aim21 interaction in vitro cause the same in vivo phenotype as TDA2 deletion showing reduced actin capping protein recruitment and increased filamentous actin at endocytic sites. Remarkably, chemically induced dimerization of Aim21 rescues the endocytic phenotype of TDA2 deletion. We also uncovered a capping protein interacting motif in Aim21, expanding its function to a fundamental cellular pathway and showing such motif exists outside mammalian cells. Furthermore, specific disruption of this motif causes the same deficit of actin capping protein recruitment and increased filamentous actin at endocytic sites as AIM21 deletion. Thus, the data indicates the Tda2-Aim21 complex functions in actin assembly primarily through capping protein regulation. Collectively, our results provide a mechanistic view of the Tda2-Aim21 complex and its function in actin network regulation at endocytic sites.

scholarly journals Structural organization of the actin-spectrin–based membrane skeleton in dendrites and soma of neurons

2017 ◽  
Vol 114 (32) ◽  
pp. E6678-E6685 ◽  
Author(s):  
Boran Han ◽  
Ruobo Zhou ◽  
Chenglong Xia ◽  
Xiaowei Zhuang
Keyword(s):  
Hippocampal Neurons ◽  
Developmental Stages ◽  
Lattice Structure ◽  
Membrane Skeleton ◽  
Capping Protein ◽  
Capping Proteins ◽  
Actin Capping Protein ◽  
Mature Neurons ◽  
Form Ring ◽  
Actin Capping

Actin, spectrin, and associated molecules form a membrane-associated periodic skeleton (MPS) in neurons. In the MPS, short actin filaments, capped by actin-capping proteins, form ring-like structures that wrap around the circumference of neurites, and these rings are periodically spaced along the neurite by spectrin tetramers, forming a quasi-1D lattice structure. This 1D MPS structure was initially observed in axons and exists extensively in axons, spanning nearly the entire axonal shaft of mature neurons. Such 1D MPS was also observed in dendrites, but the extent to which it exists and how it develops in dendrites remain unclear. It is also unclear whether other structural forms of the membrane skeleton are present in neurons. Here, we investigated the spatial organizations of spectrin, actin, and adducin, an actin-capping protein, in the dendrites and soma of cultured hippocampal neurons at different developmental stages, and compared results with those obtained in axons, using superresolution imaging. We observed that the 1D MPS exists in a substantial fraction of dendritic regions in relatively mature neurons, but this structure develops slower and forms with a lower propensity in dendrites than in axons. In addition, we observed that spectrin, actin, and adducin also form a 2D polygonal lattice structure, resembling the expanded erythrocyte membrane skeleton structure, in the somatodendritic compartment. This 2D lattice structure also develops substantially more slowly in the soma and dendrites than the development of the 1D MPS in axons. These results suggest membrane skeleton structures are differentially regulated across different subcompartments of neurons.

scholarly journals The Signaling Adaptor Eps8 Is an Essential Actin Capping Protein for Dendritic Cell Migration

Immunity ◽  
2011 ◽  
Vol 35 (3) ◽  
pp. 388-399 ◽  
Author(s):  
Emanuela Frittoli ◽  
Gianluca Matteoli ◽  
Andrea Palamidessi ◽  
Elisa Mazzini ◽  
Luigi Maddaluno ◽  
...  
Keyword(s):  
Cell Migration ◽  
Dendritic Cell ◽  
Capping Protein ◽  
Actin Capping Protein ◽  
Dendritic Cell Migration ◽  
Actin Capping

scholarly journals Actin capping protein regulates actomyosin contractility to maintain germline architecture in C. elegans

2021 ◽  
Author(s):  
Shinjini Ray ◽  
Priti Agarwal ◽  
Ronen Zaidel-Bar
Keyword(s):  
Physiological Role ◽  
Fold Increase ◽  
Actin Dynamics ◽  
Structural Defects ◽  
Capping Protein ◽  
C Elegans ◽  
Actomyosin Contractility ◽  
Actin Capping Protein ◽  
Actin Capping

Actin dynamics play an important role in the morphogenesis of cells and tissues, yet the control of actin filament growth takes place at the molecular level. A challenge in the field is to link the molecular function of actin regulators with their physiological function. Here, we report the in vivo role of the actin capping protein CAP-1 in the C. elegans germline. We show that CAP-1 is associated with actomyosin structures in the cortex and rachis, where it keeps the level of contractility in check. A 60% reduction in the level of CAP-1 leads to a 2-fold increase in F-actin and non-muscle myosin II and only a 30% increase in Arp2/3. CAP-1 depletion leads to severe structural defects in the syncytial germline and oocytes, which can be rescued by reducing myosin activity. Thus, we uncover a physiological role for actin capping protein in maintaining C. elegans fertility by regulating the level of actomyosin contractility.

scholarly journals Gelsolin-like actin-capping protein has prognostic value and promotes tumorigenesis and epithelial-mesenchymal transition via the Hippo signaling pathway in human bladder cancer

2019 ◽  
Vol 11 ◽  
pp. 175883591984123 ◽  
Author(s):  
Lyu Zhaojie ◽  
Liu Yuchen ◽  
Chen Miao ◽  
Chen Yacun ◽  
Wu Shayi ◽  
...  
Keyword(s):  
Bladder Cancer ◽  
Epithelial Mesenchymal Transition ◽  
Histologic Subtype ◽  
Mesenchymal Transition ◽  
Capping Protein ◽  
Incidence And Mortality ◽  
Actin Capping Protein ◽  
Actin Capping

Background: Transitional cell carcinoma (TCC) of the bladder, the major histologic subtype of bladder cancer, is increasing in incidence and mortality, which requires the identification of effective biomarkers. Actin-regulating proteins have recently been proposed as important antitumor druggable targets. As a gelsolin-family actin-modulating protein, CAPG (gelsolin-like actin-capping protein) generated great interest due to its crucial effects in various biological and physiological processes; however, the role and mechanism of CAPG in TCCs remain unknown. Materials and methods: Bioinformatic analysis and immunohistochemistry of clinical specimens were performed to detect the expression level of CAPG. Both in vitro and in vivo assays were used to determine the oncogenic effect of CAPG in TCCs. Male 4–5-week-old BALB/c nude mice were used for in vivo tumorigenesis assays, while SCID mice were used for in vivo metastatic assays. Affymetrix microarray was used to identify the underlying molecular mechanism. Western blot and immunofluorescence were used to validate the expression and localization of proteins. Results: CAPG was frequently upregulated in TCCs and associated with clinical aggressiveness and worse prognosis. Functional assays demonstrated that CAPG could contribute to the tumorigenesis, metastasis and epithelial-mesenchymal transition (EMT) of TCCs both in vitro and in vivo. A novel mechanism that CAPG promoted TCC development via inactivating the Hippo pathway, leading to a nucleus translocation of Yes-associated protein was suggested. Conclusions: The current study identified CAPG as a novel and critical oncogene in TCCs, supporting the pursuit of CAPG as a potential target for TCC intervention.

scholarly journals Cap Z(36/32), a barbed end actin-capping protein, is a component of the Z-line of skeletal muscle.

1987 ◽  
Vol 105 (1) ◽  
pp. 371-379 ◽  
Author(s):  
J F Casella ◽  
S W Craig ◽  
D J Maack ◽  
A E Brown
Keyword(s):  
Electron Microscopy ◽  
Skeletal Muscle ◽  
Actin Filaments ◽  
Biological Activities ◽  
Capping Protein ◽  
Actin Capping Protein ◽  
In Vitro Effects ◽  
Actin Capping

Various biological activities have been attributed to actin-capping proteins based on their in vitro effects on actin filaments. However, there is little direct evidence for their in vivo activities. In this paper, we show that Cap Z(36/32), a barbed end, actin-capping protein isolated from muscle (Casella, J. F., D. J. Maack, and S. Lin, 1986, J. Biol. Chem., 261:10915-10921) is localized to the barbed ends of actin filaments by electron microscopy and to the Z-line of chicken skeletal muscle by indirect immunofluorescence and electron microscopy. Since actin filaments associate with the Z-line at their barbed ends, these findings suggest that Cap Z(36/32) may play a role in regulating length, orienting, or attaching actin filaments to Z-discs.

scholarly journals Comparative analysis of CPI-motif regulation of biochemical functions of actin capping protein

2020 ◽  
Author(s):  
Patrick McConnell ◽  
Marlene Mekel ◽  
Alexander G. Kozlov ◽  
Olivia L. Mooren ◽  
Timothy M. Lohman ◽  
...  
Keyword(s):  
Comparative Analysis ◽  
Amino Acid Residues ◽  
Actin Assembly ◽  
Protein Families ◽  
Capping Protein ◽  
Functional Assays ◽  
Biochemical Assays ◽  
Actin Capping Protein ◽  
End Capping ◽  
Actin Capping

ABSTRACTThe heterodimeric actin capping protein (CP) is regulated by a set of proteins that contain CP-interacting (CPI) motifs. Outside of the CPI motif, the sequences of these proteins are unrelated and distinct. The CPI motif and surrounding sequences are conserved within a given protein family, when compared to those of other CPI-motif protein families. Using biochemical assays with purified proteins, we compared the ability of CPI-motif-containing peptides from different protein families to a) bind to CP, b) allosterically inhibit barbed-end capping by CP, and c) allosterically inhibit interaction of CP with V-1, another regulator of CP. We found large differences in potency among the different CPI-motif-containing peptides, and the different functional assays showed different orders of potency. These biochemical differences among the CPI-motif peptides presumably reflect interactions between CP and CPI-motif peptides involving amino-acid residues that are conserved but are not part of the strictly defined consensus, as it was originally identified in comparisons of sequences of CPI motifs(1, 2) across all protein families (1, 2). These biochemical differences may be important for conserved distinct functions of CPI-motif protein families in cells with respect to the regulation of CP activity and actin assembly near membranes.

Flightless I is a focal adhesion‐associated actin‐capping protein that regulates cell migration

2012 ◽  
Vol 26 (8) ◽  
pp. 3260-3272 ◽  
Author(s):  
Ibrahim Mohammad ◽  
Pamma D. Arora ◽  
Yeganeh Naghibzadeh ◽  
Yongqiang Wang ◽  
Jeff Li ◽  
...  
Keyword(s):  
Cell Migration ◽  
Focal Adhesion ◽  
Capping Protein ◽  
Actin Capping Protein ◽  
Actin Capping

scholarly journals Interactions between the Evolutionarily Conserved, Actin-related Protein, Arp11, Actin, and Arp1

2003 ◽  
Vol 14 (7) ◽  
pp. 2645-2654 ◽  
Author(s):  
D. Mark Eckley ◽  
Trina A. Schroer
Keyword(s):  
Cultured Cells ◽  
Related Protein ◽  
Capping Protein ◽  
Binding Domains ◽  
Actin Capping Protein ◽  
Multiple Species ◽  
Pointed End ◽  
Actin Capping ◽  
Cargo Binding

The dynein activator dynactin is a multiprotein complex with distinct microtubule- and cargo-binding domains. The cargo-binding domain contains a short, actin-like filament of the actin-related protein Arp1, a second actin-related protein, Arp11, and conventional actin. The length of this filament is invariant in dynactin isolated from multiple species and tissues, suggesting that activities that regulate Arp1 polymerization are important for dynactin assembly. Arp11 is present in a protein complex localized at the pointed end of the Arp1 minifilament, whereas actin capping protein (CapZ) is present at the barbed end. Either might cooperate with conventional actin to cap Arp1. We tested the ability of Arp11 to interact with conventional actin and found it could coassemble. Like Arp1, cytosolic Arp11 is found only in dynactin, suggesting that Arp11 and free cytosolic actin do not interact significantly. Recombinant Arp11 and Arp1 were demonstrated to interact by coprecipitation. We developed an in vivo assay for Arp11–Arp1 interaction based on previous observations that Arp1 forms filamentous assemblies when overexpressed in cultured cells. Arp11 significantly decreases the formation of these organized Arp1 assemblies. Finally, this assay was used to confirm the identity of a putative Arp11 homolog in Drosophila melanogaster.

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