Hormones and the Cytoskeleton of Animals and Plants

Loof, Arnold De; Broeck, Jozef Vanden; Janssen, Ine

doi:10.1016/s0074-7696(08)62505-x

Cited by 23 publications

(19 citation statements)

References 286 publications

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“…Sinha and Wagner [1987] pointed out that microtubules play a role in exocrine cells, which secrete their products by exocytosis. Tubulin is one of the cytoskeletal elements involved in a variety of cellular processes, such as meiosis and mitosis, spatial distribution of cell organelles, and cellular responses to membrane events such as endocytosis and exocytosis [De Loof et al, 1996]. Ultrastructural studies on microtubules in telocytes in the lamina propria of human urethra were reported by Gevaert et al [2012].…”

Section: Discussionmentioning

confidence: 99%

New Description of Telocyte Sheaths in the Bovine Uterine Tube: An Immunohistochemical and Scanning Microscopic Study

Abd‐Elhafeez

Soliman

2016

Cells Tissues Organs

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Telocytes are a special type of interstitial cells characterized by distinctive cellular extensions with alternating thin segments (podomers) and dilations (podoms). Telocytes establish contact with various cells and structures, but their role in the regulation of the function of many cell types is still obscure. The aim of the current study was to investigate the morphology, histochemistry, and immunohistochemistry of telocytes, and their distribution, organization, and morphometric measurements in different layers of the adult bovine uterine tube. Telocytes showed positive immunostaining for CD117, S-100 protein, vimentin, desmin, α-smooth muscle actin, tubulin, laminin, estrogen receptor-α, and progesterone receptor. They were organized in different types of sheaths: subepithelial, inner/outer perimuscular, and intramuscular sheaths. Telocytes were scattered in the lamina propria, in the muscular layer, and the serosa. According to their size, they were grouped into different types of telocytes: small, large, and giant telocytes. Small telocytes were the most common type and located in all layers; large telocytes were observed in the epithelium, lamina propria, and inner/outer perimuscular and intramuscular sheaths, and giant telocytes were found in the external layer of the outer perimuscular sheath. Telocytes were connected by thin and thick telopodes (fenestrated membranes). Fenestrated membranes enabled connections between telocytes along the entire muscular wall of the uterine tube. Telocytes established an extensive biological network of different types of cells and structures, including epithelial, muscular, and mast cells, blood vessels, glomus, and nerve fibers. We hypothesize that telocytes help to organize the functional coordination between different types of cells in the uterine tube.

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Section: Discussionmentioning

confidence: 99%

New Description of Telocyte Sheaths in the Bovine Uterine Tube: An Immunohistochemical and Scanning Microscopic Study

Abd‐Elhafeez

Soliman

2016

Cells Tissues Organs

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“…21 and 22). To test whether changes in the organization of the cytoskeleton may be related to parallel changes in CPT-I activity, hepatocytes were incubated with colchicine (a microtubule (23,24). As shown in Table II, neither colchicine nor cytochalasin B affected CPT-I activity.…”

Section: Effect Of Mild Trypsin Digestion On Cpt-i Activity-in a Firstmentioning

confidence: 99%

Malonyl-CoA-independent Acute Control of Hepatic Carnitine Palmitoyltransferase I Activity

Velasco¹,

Geelen²,

Pulgar³

et al. 1998

Journal of Biological Chemistry

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The mechanism of malonyl-CoA-independent acute control of hepatic carnitine palmitoyltransferase I (CPT-I) activity was investigated. In a first series of experiments, the possible involvement of the cytoskeleton in the control of CPT-I activity was studied. The results of these investigations can be summarized as follows. (i) Very mild treatment of permeabilized hepatocytes with trypsin produced around 50% stimulation of CPT-I activity. This effect was absent in cells that had been pretreated with okadaic acid (OA) and seemed to be due to the action of trypsin on cell component(s) distinct from CPT-I. (ii) Incubation of intact hepatocytes with 3,3-iminodipropionitrile, a disruptor of intermediate filaments, increased CPT-I activity in a non-additive manner with respect to OA. Taxol, a stabilizer of the cytoskeleton, prevented the OA-and 3,3-iminodipropionitrile-induced stimulation of CPT-I. (iii) CPT-I activity in isolated mitochondria was depressed in a dose-dependent fashion by the addition of a total cytoskeleton fraction and a cytokeratin-enriched cytoskeletal fraction, the latter being 3 times more potent than the former. In a second series of experiments, the possible link between Ca 2؉ /calmodulin-dependent protein kinase II (Ca 2؉ /CM-PKII) and the cytoskeleton was studied in the context of CPT-I regulation. The data of these experiments indicate that (i) purified Ca 2؉ /CM-PKII activated CPT-I in permeabilized hepatocytes but not in isolated mitochondria, (ii) purified Ca 2؉ /CM-PKII abrogated the inhibition of CPT-I of isolated mitochondria induced by a cytokeratin-enriched fraction, and (iii) the Ca 2؉ /CM-PKII inhibitor KN-62 prevented the OA-induced phosphorylation of cytokeratins in intact hepatocytes. Results thus support a novel mechanism of short-term control of hepatic CPT-I activity which may rely on the cascade Ca 2؉ /CM-PKII activation 3 cytokeratin phosphorylation 3 CPT-I de-inhibition.Mitochondrial fatty acid oxidation in liver provides a major source of energy to this organ and supplies extrahepatic tissues with ketone bodies as a glucose-replacing fuel (1, 2). Carnitine palmitoyltransferase I (CPT-I), 1 the carnitine palmitoyltransferase of the mitochondrial outer membrane, catalyzes the pace-setting step of long-chain fatty acid translocation into the mitochondrial matrix (1-5). Moreover, recent determination of flux control coefficients of the enzymes involved in hepatic long-chain fatty acid oxidation shows that CPT-I plays a pivotal role in controlling the flux through this pathway under different substrate concentrations and pathophysiological states (6, 7). CPT-I is subject to long-term regulation in response to alterations in the nutritional and hormonal status of the animal (1, 2, 5). Short-term control of CPT-I activity involves inhibition by malonyl-CoA, the product of the reaction catalyzed by acetyl-CoA carboxylase (8). Since the latter enzyme is a key regulatory site of fatty acid synthesis de novo (cf. Refs. 1-5), malonyl-CoA inhibition of CPT-I allows an elegant explanati...

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“…Later, other non-genomic effects became also known, e.g. on the cytoskeleton (De Loof et al, 1996), on behavior and on Ca 2+ -metabolism. However, despite all efforts to identify them by classical biochemical approaches, the picture of the nature of membrane receptors of steroid hormones as well as their localization in different tissues remains rather inconclusive.…”

Section: Which Steroid-and Sesquiterpenoid Hormones and Their Receptomentioning

confidence: 99%

The essence of female–male physiological dimorphism: Differential Ca2+-homeostasis enabled by the interplay between farnesol-like endogenous sesquiterpenoids and sex-steroids? The Calcigender paradigm

Loof

2015

General and Comparative Endocrinology

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Ca(2+) is the most omnipresent pollutant on earth, in higher concentrations a real threat to all living cells. When [Ca(2+)]i rises above 100 nM (=resting level), excess Ca(2+) needs to be confined in the SER and mitochondria, or extruded by the different Ca(2+)-ATPases. The evolutionary origin of eggs and sperm cells has a crucial, yet often overlooked link with Ca(2+)-homeostasis. Because there is no goal whatsoever in evolution, gametes did neither originate "with the purpose" of generating a progeny nor of increasing fitness by introducing meiosis. The explanation may simply be that females "invented the trick" to extrude eggs from their body as an escape strategy for getting rid of toxic excess Ca(2+) resulting from a sex-hormone driven increased influx into particular cells and tissues. The production of Ca(2+)-rich milk, seminal fluid in males and all secreted proteins by eukaryotic cells may be similarly explained. This view necessitates an upgrade of the role of the RER-Golgi system in extruding Ca(2+). In the context of insect metamorphosis, it has recently been (re)discovered that (some isoforms of) Ca(2+)-ATPases act as membrane receptors for some types of lipophilic ligands, in particular for endogenous farnesol-like sesquiterpenoids (FLS) and, perhaps, for some steroid hormones as well. A novel paradigm, tentatively named "Calcigender" emerges. Its essence is: gender-specific physiotypes ensue from differential Ca(2+)-homeostasis enabled by genetic differences, farnesol/FLS and sex hormones. Apparently the body of reproducing females gets temporarily more poisoned by Ca(2+) than the male one, a selective benefit rather than a disadvantage.

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Hormones and the Cytoskeleton of Animals and Plants

Cited by 23 publications

References 286 publications

New Description of Telocyte Sheaths in the Bovine Uterine Tube: An Immunohistochemical and Scanning Microscopic Study

New Description of Telocyte Sheaths in the Bovine Uterine Tube: An Immunohistochemical and Scanning Microscopic Study

Malonyl-CoA-independent Acute Control of Hepatic Carnitine Palmitoyltransferase I Activity

The essence of female–male physiological dimorphism: Differential Ca2+-homeostasis enabled by the interplay between farnesol-like endogenous sesquiterpenoids and sex-steroids? The Calcigender paradigm

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