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Seven kinds of intermediate filament networks in the cytoplasm of polarized cells: structure and function.

Iwatsuki H, Suda M - Acta Histochem Cytochem (2010)

Bottom Line: However, little information exists on the structure of the IF networks performing these functions.We have clarified the existence of seven kinds of IF networks in the cytoplasm of diverse polarized cells: an apex network just under the terminal web, a peripheral network lying just beneath the cell membrane, a granule-associated network surrounding a mass of secretory granules, a Golgi-associated network surrounding the Golgi apparatus, a radial network locating from the perinuclear region to the specific area of the cell membrane, a juxtanuclear network surrounding the nucleus, and an entire cytoplasmic network.In this review, we describe these seven kinds of IF networks and discuss their biological roles.

View Article: PubMed Central - PubMed

Affiliation: Department of Anatomy, Kawasaki Medical School, Matsushima 577, Kurashiki 701-0192, Japan. iwatsuki@med.kawasaki-m.ac.jp

ABSTRACT
Intermediate filaments (IFs) are involved in many important physiological functions, such as the distribution of organelles, signal transduction, cell polarity and gene regulation. However, little information exists on the structure of the IF networks performing these functions. We have clarified the existence of seven kinds of IF networks in the cytoplasm of diverse polarized cells: an apex network just under the terminal web, a peripheral network lying just beneath the cell membrane, a granule-associated network surrounding a mass of secretory granules, a Golgi-associated network surrounding the Golgi apparatus, a radial network locating from the perinuclear region to the specific area of the cell membrane, a juxtanuclear network surrounding the nucleus, and an entire cytoplasmic network. In this review, we describe these seven kinds of IF networks and discuss their biological roles.

No MeSH data available.


Immunoelectron microscopic staining of keratin 18 (K18) in absorptive cells of the rabbit duodenum. Keratin 18-positive filaments (arrowheads) are localized just under the terminal web (asterisk) and anchored to a desmosome (arrow). Some of them are observed in the terminal web and in the upper cytoplasm of the terminal web. Bar=0.5 µm.
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Figure 5: Immunoelectron microscopic staining of keratin 18 (K18) in absorptive cells of the rabbit duodenum. Keratin 18-positive filaments (arrowheads) are localized just under the terminal web (asterisk) and anchored to a desmosome (arrow). Some of them are observed in the terminal web and in the upper cytoplasm of the terminal web. Bar=0.5 µm.

Mentions: Franke et al. [33] were the first to note that keratin is concentrated in the terminal web and in a special zone subjacent to the terminal web of the intestinal absorptive cells. As shown in Figure 4, this apex network of the rabbit absorptive cells is composed of keratin 5/18 filaments [63]. This network develops very little in the crypt cells, and then develops steadily until the cells move upward onto the villus base. It was confirmed by an immunoelectron microscopical study that this network is tightly anchored to the desmosomes and extends into the terminal web (Fig. 5). Keratin IFs can anchor to desmosomes by adaptor proteins of desmoplakin [141] and connect to actin filaments in the terminal web by plastin 1 [49]. Therefore, this network may serve to maintain cell-cell contact and may be involved in reinforcement of the terminal web. It has been reported that epithelial cells exhibiting a polarized structure require the keratin filament-organization at the apical domain, and that a deficiency in this organization leads to the disruption of cell polarity [4, 115, 130]. Therefore, the apex network may also participate in the generation of cell polarity.


Seven kinds of intermediate filament networks in the cytoplasm of polarized cells: structure and function.

Iwatsuki H, Suda M - Acta Histochem Cytochem (2010)

Immunoelectron microscopic staining of keratin 18 (K18) in absorptive cells of the rabbit duodenum. Keratin 18-positive filaments (arrowheads) are localized just under the terminal web (asterisk) and anchored to a desmosome (arrow). Some of them are observed in the terminal web and in the upper cytoplasm of the terminal web. Bar=0.5 µm.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2875862&req=5

Figure 5: Immunoelectron microscopic staining of keratin 18 (K18) in absorptive cells of the rabbit duodenum. Keratin 18-positive filaments (arrowheads) are localized just under the terminal web (asterisk) and anchored to a desmosome (arrow). Some of them are observed in the terminal web and in the upper cytoplasm of the terminal web. Bar=0.5 µm.
Mentions: Franke et al. [33] were the first to note that keratin is concentrated in the terminal web and in a special zone subjacent to the terminal web of the intestinal absorptive cells. As shown in Figure 4, this apex network of the rabbit absorptive cells is composed of keratin 5/18 filaments [63]. This network develops very little in the crypt cells, and then develops steadily until the cells move upward onto the villus base. It was confirmed by an immunoelectron microscopical study that this network is tightly anchored to the desmosomes and extends into the terminal web (Fig. 5). Keratin IFs can anchor to desmosomes by adaptor proteins of desmoplakin [141] and connect to actin filaments in the terminal web by plastin 1 [49]. Therefore, this network may serve to maintain cell-cell contact and may be involved in reinforcement of the terminal web. It has been reported that epithelial cells exhibiting a polarized structure require the keratin filament-organization at the apical domain, and that a deficiency in this organization leads to the disruption of cell polarity [4, 115, 130]. Therefore, the apex network may also participate in the generation of cell polarity.

Bottom Line: However, little information exists on the structure of the IF networks performing these functions.We have clarified the existence of seven kinds of IF networks in the cytoplasm of diverse polarized cells: an apex network just under the terminal web, a peripheral network lying just beneath the cell membrane, a granule-associated network surrounding a mass of secretory granules, a Golgi-associated network surrounding the Golgi apparatus, a radial network locating from the perinuclear region to the specific area of the cell membrane, a juxtanuclear network surrounding the nucleus, and an entire cytoplasmic network.In this review, we describe these seven kinds of IF networks and discuss their biological roles.

View Article: PubMed Central - PubMed

Affiliation: Department of Anatomy, Kawasaki Medical School, Matsushima 577, Kurashiki 701-0192, Japan. iwatsuki@med.kawasaki-m.ac.jp

ABSTRACT
Intermediate filaments (IFs) are involved in many important physiological functions, such as the distribution of organelles, signal transduction, cell polarity and gene regulation. However, little information exists on the structure of the IF networks performing these functions. We have clarified the existence of seven kinds of IF networks in the cytoplasm of diverse polarized cells: an apex network just under the terminal web, a peripheral network lying just beneath the cell membrane, a granule-associated network surrounding a mass of secretory granules, a Golgi-associated network surrounding the Golgi apparatus, a radial network locating from the perinuclear region to the specific area of the cell membrane, a juxtanuclear network surrounding the nucleus, and an entire cytoplasmic network. In this review, we describe these seven kinds of IF networks and discuss their biological roles.

No MeSH data available.