Characterization of the EF-Hand Calcium-Binding Domains of Human Plastins

Khassan, Oleg; Jensen, Katharine V.; Woodman, Andrew G.; Vogel, Hans J.; Ishida, Hiroaki

doi:10.1007/978-1-4939-9030-6_16

Cited by 3 publications

(5 citation statements)

References 45 publications

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“…Interestingly, comparisons of the three plastin isoforms show a much lower amino acid identity at the N-terminal EF-hand domains than the higher conserved actin-binding domains. Thus, several studies compared the plastin isoforms regarding their Ca 2+ sensitivities and Ca 2+ -dependent functions [33,[47][48][49].…”

Section: Influence Of Intracellular Calcium On Pls3-dependent Processesmentioning

confidence: 99%

“…To gain further insight into the process of Ca 2+ -binding to the EF-hands as well as into kinetic and structural details on Ca 2+ -regulated domains of plastins, three biophysical methods have been used: surface plasmon resonance studies, isothermal titration calorimetry studies, and nuclear magnetic resonance spectroscopy [48]. In terms of Ca 2+ -regulated function, a crucial role of the regulatory helix 5 (H5) linker region localized between the second EF-hand motif and the first CH1 domain of ABD1 has been suggested, which may even differ between the plastin isoforms.…”

Section: Influence Of Intracellular Calcium On Pls3-dependent Processesmentioning

confidence: 99%

“…In terms of Ca 2+ -regulated function, a crucial role of the regulatory helix 5 (H5) linker region localized between the second EF-hand motif and the first CH1 domain of ABD1 has been suggested, which may even differ between the plastin isoforms. Precisely, the H5 region of PLS3 (TPL-EF-H5 construct) is not displaced by the bee venom peptide melittin, unlike a possible displacement in PLS2 (LPL-EF-H5 construct) [48].…”

Section: Influence Of Intracellular Calcium On Pls3-dependent Processesmentioning

confidence: 99%

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Plastin 3 in health and disease: a matter of balance

Wolff

Strathmann

Müller

et al. 2021

Cell. Mol. Life Sci.

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For a long time, PLS3 (plastin 3, also known as T-plastin or fimbrin) has been considered a rather inconspicuous protein, involved in F-actin-binding and -bundling. However, in recent years, a plethora of discoveries have turned PLS3 into a highly interesting protein involved in many cellular processes, signaling pathways, and diseases. PLS3 is localized on the X-chromosome, but shows sex-specific, inter-individual and tissue-specific expression variability pointing towards skewed X-inactivation. PLS3 is expressed in all solid tissues but usually not in hematopoietic cells. When escaping X-inactivation, PLS3 triggers a plethora of different types of cancers. Elevated PLS3 levels are considered a prognostic biomarker for cancer and refractory response to therapies. When it is knocked out or mutated in humans and mice, it causes osteoporosis with bone fractures; it is the only protein involved in actin dynamics responsible for osteoporosis. Instead, when PLS3 is upregulated, it acts as a highly protective SMN-independent modifier in spinal muscular atrophy (SMA). Here, it seems to counteract reduced F-actin levels by restoring impaired endocytosis and disturbed calcium homeostasis caused by reduced SMN levels. In contrast, an upregulation of PLS3 on wild-type level might cause osteoarthritis. This emphasizes that the amount of PLS3 in our cells must be precisely balanced; both too much and too little can be detrimental. Actin-dynamics, regulated by PLS3 among others, are crucial in a lot of cellular processes including endocytosis, cell migration, axonal growth, neurotransmission, translation, and others. Also, PLS3 levels influence the infection with different bacteria, mycosis, and other pathogens.

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Section: Influence Of Intracellular Calcium On Pls3-dependent Processesmentioning

confidence: 99%

Section: Influence Of Intracellular Calcium On Pls3-dependent Processesmentioning

confidence: 99%

Section: Influence Of Intracellular Calcium On Pls3-dependent Processesmentioning

confidence: 99%

See 1 more Smart Citation

Plastin 3 in health and disease: a matter of balance

Wolff

Strathmann

Müller

et al. 2021

Cell. Mol. Life Sci.

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show abstract

“…Consequently, this regulatory region has been termed the switch helix, as it appears to be involved in switching the actin-bundling on-and-off. Recent studies have shown that the same mechanism, with a regulatory switch helix, also occurs in the human T-plastin headpiece, albeit at slightly different calcium concentrations 36 – 38 .…”

Section: Introductionmentioning

confidence: 92%

The Dictyostelium discoideum FimA protein, unlike yeast and plant fimbrins, is regulated by calcium similar to mammalian plastins

Ishida,

Woodman,

Kitada

et al. 2023

Sci Rep

Self Cite

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Plastins, also known as fimbrins, are highly conserved eukaryotic multidomain proteins that are involved in actin-bundling. They all contain four independently folded Calponin Homology-domains and an N-terminal headpiece that is comprised of two calcium-binding EF-hand motifs. Since calcium-binding has been shown to be integral to regulating the activity of the three mammalian plastin proteins, we decided to study the properties of the headpiece regions of fimbrins from the model plant Arabidopsis thaliana, the yeasts Saccharomyces cerevisiae and Schizosaccharomyces pombe and the amoeba Dictyostelium discoideum. Of these protein domains only the FimA headpiece from the amoeba protein possesses calcium binding properties. Structural characterization of this protein domain by multidimensional NMR and site-directed mutagenesis studies indicates that this EF-hand region of FimA also contains a regulatory ‘switch helix’ that is essential to regulating the activity of the human L-plastin protein. Interestingly this regulatory helical region seems to be lacking in the plant and yeast proteins and in fimbrins from all other nonmotile systems. Typical calmodulin antagonists can displace the switch-helix from the FimA headpiece, suggesting that such drugs can deregulate the Ca2+-regulation of the actin-bunding in the amoeba, thereby making it a useful organism for drug screening against mammalian plastins.

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“…The latter bind strongly to actin filaments and their tandem arrangement enables F-actin bundling and crosslinking. This activity is regulated by binding of calcium to the N-terminal EF-hands, which inhibits actin-bundling by PLS3, but not actin-binding ( Schwebach et al, 2017 ; Khassan et al, 2019 ). PLS3 has been shown to play a role in fundamental cellular processes, including cell migration, cell-cell contact and endocytosis, which further explain how PLS3 contributes to cancer metastasis, cardiovascular defects, and spinal muscular atrophy ( Hagiwara et al, 2011 ; Brun et al, 2014 ; Wottawa et al, 2017 ; Garbett et al, 2020 ; Pan et al, 2020 ).…”

Section: Introductionmentioning

confidence: 99%

The actin-bundling protein, PLS3, is part of the mechanoresponsive machinery that regulates osteoblast mineralization

Chin,

Unnold-Cofre,

Naismith

et al. 2023

Front. Cell Dev. Biol.

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Plastin-3 (PLS3) is a calcium-sensitive actin-bundling protein that has recently been linked to the development of childhood-onset osteoporosis. Clinical data suggest that PLS3 mutations lead to a defect in osteoblast function, however the underlying mechanism remains elusive. To investigate the role of PLS3 in bone mineralization, we generated MC3T3-E1 preosteoblast cells that are stably depleted of PLS3. Analysis of osteogenic differentiation of control and PLS3 knockdown (PLS3 KD) cells showed that depletion of PLS3 does not alter the first stage of osteoblast mineralization in which a collagen matrix is deposited, but severely affects the subsequent mineralization of that matrix. During this phase, osteoblasts heavily rely on mechanosensitive signaling pathways to sustain mineral deposition in response to increasing stiffness of the extracellular matrix (ECM). PLS3 prominently localizes to focal adhesions (FAs), which are intricately linked to mechanosensation. In line with this, we observed that depletion of PLS3 rendered osteoblasts unresponsive to changes in ECM stiffness and showed the same cell size, FA lengths and number of FAs when plated on soft (6 kPa) versus stiff (100 kPa) substrates in contrast to control cells, which showed an increased in each of these parameters when plated on 100 kPa substrates. Defective cell spreading of PLS3 KD cells on stiff substrates could be rescued by expression of wildtype PLS3, but not by expression of three PLS3 mutations that were identified in patients with early onset osteoporosis and that have aberrant actin-bundling activity. Altogether, our results show that actin-bundling by PLS3 is part of the mechanosensitive mechanism that promotes osteoblast mineralization and thus begins to elucidate how PLS3 contributes to the development of bone defects such as osteoporosis.

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Characterization of the EF-Hand Calcium-Binding Domains of Human Plastins

Cited by 3 publications

References 45 publications

Plastin 3 in health and disease: a matter of balance

Plastin 3 in health and disease: a matter of balance

The Dictyostelium discoideum FimA protein, unlike yeast and plant fimbrins, is regulated by calcium similar to mammalian plastins

The actin-bundling protein, PLS3, is part of the mechanoresponsive machinery that regulates osteoblast mineralization

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