In polarized motile cells, stress fibers display specific three-dimensional organization. Ventral stress fibers, attached to focal adhesions at both ends, are restricted to the basal side of the cell and nonprotruding cell sides. Dorsal fibers, transverse actin arcs, and perinuclear actin fibers emanate from protruding cell front toward the nucleus and toward apical side of the cell. Perinuclear cap fibers further extend above the nucleus, associate with nuclear envelope through LINC (linker of nucleoskeleton and cytoskeleton) complex and terminate in focal adhesions at cell rear. How are perinuclear actin fibers formed is poorly understood. We show that the formation of perinuclear actin fibers requires dorsal stress fibers that polymerize from focal adhesions at leading edge, and transverse actin arcs that are interconnected with dorsal fibers in spots rich in α-actinin-1. During cell polarization, the interconnected dorsal fibers and transverse arcs move from leading edge toward dorsal side of the cell. As they move, transverse arcs associate with one end of stress fibers present at nonprotruding cell sides, move them above the nucleus thus forming perinuclear actin fibers. Furthermore, the formation of perinuclear actin fibers induces temporal rotational movement of the nucleus resulting in nuclear reorientation to the direction of migration. These results suggest that the network of dorsal fibers, transverse arcs, and perinuclear fibers transfers mechanical signal between the focal adhesions and nuclear envelope that regulates the nuclear reorientation in polarizing cells.

• Klíčová slova
• actin dorsal fibers, cell polarity, nuclear reorientation, perinuclear actin fibers, transverse arcs, α-actinin-1,
• MeSH
• aktinin fyziologie   MeSH
• aktiny fyziologie   MeSH
• buněčné jádro fyziologie   MeSH
• buněčné linie MeSH
• buněčný převod mechanických signálů fyziologie   MeSH
• fibroblasty fyziologie   MeSH
• fokální adheze fyziologie   MeSH
• kontraktilní svazky fyziologie   MeSH
• krysa rodu Rattus MeSH
• lidé MeSH
• pohyb buněk fyziologie   MeSH
• pohyb fyziologie   MeSH
• polarita buněk fyziologie   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• lidé MeSH
• zvířata MeSH
• Publikační typ
• práce podpořená grantem MeSH
• úvodníky MeSH
• Názvy látek
• aktinin MeSH
• aktiny MeSH

Stress fibers are actin bundles encompassing actin filaments, actin-crosslinking, and actin-associated proteins that represent the major contractile system in the cell. Different types of stress fibers assemble in adherent cells, and they are central to diverse cellular processes including establishment of the cell shape, morphogenesis, cell polarization, and migration. Stress fibers display specific cellular organization and localization, with ventral fibers present at the basal side, and dorsal fibers and transverse actin arcs rising at the cell front from the ventral to the dorsal side and toward the nucleus. Perinuclear actin cap fibers are a specific subtype of stress fibers that rise from the leading edge above the nucleus and terminate at the cell rear forming a dome-like structure. Perinuclear actin cap fibers are fixed at three points: both ends are anchored in focal adhesions, while the central part is physically attached to the nucleus and nuclear lamina through the linker of nucleoskeleton and cytoskeleton (LINC) complex. Here, we discuss recent work that provides new insights into the mechanism of assembly and the function of these actin stress fibers that directly link extracellular matrix and focal adhesions with the nuclear envelope.

• Klíčová slova
• Dorsal fibers, Focal adhesions, LINC, Perinuclear actin cap, Stress fibers, α-Actinin,
• MeSH
• aktin zastřešující proteiny metabolismus   MeSH
• buněčné jádro metabolismus   MeSH
• buněčný převod mechanických signálů fyziologie   MeSH
• fokální adheze fyziologie   MeSH
• jaderný obal metabolismus   MeSH
• kontraktilní svazky fyziologie   MeSH
• lidé MeSH
• pohyb buněk fyziologie   MeSH
• polarita buněk fyziologie   MeSH
• tvar buňky fyziologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• aktin zastřešující proteiny MeSH

We describe a unique benign mesenchymal tumor in paraspinal location in a 13-year-old patient with Gardner's syndrome. The Gardner's syndrome in this patient consisted of multiple (more than 100) polyps throughout the entire colon with most in the cecum and rectum, three osteomas in the frontal area of the skull and one in the third right rib, and multiple superficial skin tumors. One of these cutaneous tumors was excised and histologically diagnosed as an epidermal cyst. Both father and uncle of this patient suffered from Gardner's syndrome as well. Microscopically the mesenchymal tumor was histologically different from nuchal type fibroma and fibromatosis. It consisted of a diffusely-growing fibrous mass composed of dense collagenous fibers and relatively numerous, bland-looking, spindle-shaped cells. The collagen fibers had haphazard spacing with no lobular arrangement. The collagen fibers were of a very coarse quality. No entrapment of adipose tissue, skeletal muscle or peripheral nerves was seen in the lesion. Immunohistochemically the tumor was vimentin positive and smooth muscle actin, muscle-specific actin, S-100 protein, cytokeratin and desmin negative.

• MeSH
• diferenciální diagnóza MeSH
• fibrom komplikace   patologie   chirurgie   MeSH
• Gardnerův syndrom komplikace   patologie   MeSH
• lidé MeSH
• mezoderm patologie   MeSH
• mladiství MeSH
• nádory hlavy a krku komplikace   patologie   chirurgie   MeSH
• Check Tag
• lidé MeSH
• mladiství MeSH
• mužské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• kazuistiky MeSH