関: filopodia、filopodial

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/02/24 12:18:14」(JST)

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This electron micrograph shows exaggerated filopodia with club-like shape induced by formin mDia2 in cultured cells. These filopodia are filled with bundled actin filaments which were born in and converged from the lamellipodial network.

Filopodia (also microspikes) are slender cytoplasmic projections that extend beyond the leading edge of lamellipodia in migrating cells.^[1] They contain actin filaments cross-linked into bundles by actin-binding proteins, e.g. fascin and fimbrin.^[2] Filopodia form focal adhesions with the substratum, linking it to the cell surface.^[3] Many types of migrating cells display filopodia, which are thought to be involved in both sensation of chemotropic cues, and resulting changes in directed locomotion.

Activation of the Rho family of small Ras-related GTPases, particularly cdc42 and their downstream intermediates results in the polymerization of actin fibers by Ena/Vasp homology proteins.^[4] Growth factors bind to receptor tyrosine kinases resulting in the polymerization of actin filaments, which, when cross-linked, make up the supporting cytoskeletal elements of filopodia. Rho activity also results in activation by phosphorylation of ezrin-moesin-radixin family proteins that link actin filaments to the filopodia membrane.^[4]

Filopodia have roles in sensing, migration and cell-cell interaction.^[1] To close a wound in vertebrates, growth factors stimulate the formation of filopodia in fibroblasts to direct fibroblast migration and wound closure.^[5] In developing neurons, filopodia extend from the growth cone at the leading edge. In neurons deprived of filopodia by partial inhibition of actin filaments polymerization, growth cone extension continues as normal but direction of growth is disrupted and highly irregular.^[5] Filopodia-like projections have also been linked to dendrite creation when new synapses are formed in the brain.^[6]^[7] In macrophages, filopodia act as phagocytic tentacles and pull bound objects towards the cell for phagocytosis.^[8]

Filopodia are also used for movement of bacteria between cells, so as to evade the host immune system. The intracellular bacteria Ehrlichia are transported between cells through the host cell filopodia induced by the pathogen during initial stages of infection.^[9] Viruses were shown to be transported along filopodia toward the cell body, leading to cell infection.^[10] Directed transport of receptor-bound epidermal growth factor (EGF) along filopodia has also been described, supporting the proposed sensing function of filopodia.^[11]

References

^ ^a ^b Mattila PK, Lappalainen P (June 2008). "Filopodia: molecular architecture and cellular functions". Nat. Rev. Mol. Cell Biol. 9 (6): 446–54. doi:10.1038/nrm2406. PMID 18464790.
^ Hanein D, Matsudaira P, DeRosier DJ (October 1997). "Evidence for a conformational change in actin induced by fimbrin (N375) binding". J. Cell Biol. 139 (2): 387–96. doi:10.1083/jcb.139.2.387. PMC 2139807. PMID 9334343.
^ Molecular Cell Biology Fifth Edition Lodish, Berk, Matsudaira, Kaiser, Krieger, Scott, Zipursky, Darnell. pg. 821, 823 2004 by W.H. Freeman and Company.
^ ^a ^b Ohta Y, Suzuki N, Nakamura S, Hartwig JH, Stossel TP (March 1999). "The small GTPase RalA targets filamin to induce filopodia". Proc. Natl. Acad. Sci. U.S.A. 96 (5): 2122–8. doi:10.1073/pnas.96.5.2122. PMC 26747. PMID 10051605.
^ ^a ^b Bentley D, Toroian-Raymond A (1986). "Disoriented pathfinding by pioneer neurone growth cones deprived of filopodia by cytochalasin treatment". Nature 323 (6090): 712–5. doi:10.1038/323712a0. PMID 3773996.
^ Beardsley, John (June 1999). "Getting Wired". Scientific American.
^ Maletic-Savatic, M.; Malinow R. (June 1999). "Rapid Dendritic Morphogenesis in CA1 Hippocampal Dendrites Induced by Synaptic Activity". Science. doi:10.1126/science.283.5409.1923.
^ Kress H, Stelzer EH, Holzer D, Buss F, Griffiths G, Rohrbach A (2007). "Filopodia act as phagocytic tentacles and pull with discrete steps and a load-dependent velocity". Proc. Natl. Acad. Sci. U.S.A. 104 (28): 11633–11638. doi:10.1073/pnas.0702449104. PMC 1913848. PMID 17620618.
^ Thomas S, Popov VL, Walker DH (2010) Exit Mechanisms of the Intracellular Bacterium Ehrlichia" PLoS ONE 5(12) e15775. http://www.plosone.org/article/info:doi%2F10.1371%2Fjournal.pone.0015775
^ Lehmann MJ, Sherer NM, Marks CB, Pypaert M, Mothes W (2005). "Actin- and myosin-driven movement of viruses along filopodia precedes their entry into cells.". J Cell Biol 170 (2): 317–325. doi:10.1083/jcb.200503059. PMC 2171413. PMID 16027225.
^ Lidke, DS; Lidke, KA; Rieger, B; Jovin, TM; Arndt-Jovin, DJ (Aug 15, 2005). "Reaching out for signals: filopodia sense EGF and respond by directed retrograde transport of activated receptors.". The Journal of Cell Biology 170 (4): 619–26. doi:10.1083/jcb.200503140. PMC 2171515. PMID 16103229.

External links

MBInfo - Filopodia
MBInfo - Filopodia Assembly
[1]

English Journal

Effects of the nanotopographic surface structure of commercially pure titanium following anodization-hydrothermal treatment on gene expression and adhesion in gingival epithelial cells.

Takebe J1, Miyata K2, Miura S2, Ito S2.
Materials science & engineering. C, Materials for biological applications.Mater Sci Eng C Mater Biol Appl.2014 Sep 1;42:273-9. doi: 10.1016/j.msec.2014.05.040. Epub 2014 May 27.
The long-term stability and maintenance of endosseous implants with anodized-hydrothermally treated commercially pure titanium surfaces and a nanotopographic structure (SA-treated c.p.Ti) depend on the barrier function provided by the interface between the transmucosal portion of the implant surface
PMID 25063119

A spatiotemporally defined in vitro microenvironment for controllable signal delivery and drug screening.

Kuo CT1, Liu HK, Huang GS, Chang CH, Chen CL, Chen KC, Yun-Ju Huang R, Lin CH, Lee H, Huang CS, Wo AM.
The Analyst.Analyst.2014 Aug 4. [Epub ahead of print]
Cancer metastasis and drug resistance are important malignant tumor phenotypes that cause roughly 90% mortality in human cancers. Current therapeutic strategies, however, face substantial challenges partially due to a lack of applicable pre-clinical models and drug-screening platforms. Notably, micr
PMID 25089836

Glycine modulates membrane potential, cell volume, and phagocytosis in murine microglia.

Komm B1, Beyreis M, Kittl M, Jakab M, Ritter M, Kerschbaum HH.
Amino acids.Amino Acids.2014 Aug;46(8):1907-17. doi: 10.1007/s00726-014-1745-8. Epub 2014 Apr 24.
Phagocytes form engulfment pseudopodia at the contact area with their target particle by a process resembling cell volume (CV) regulatory mechanisms. We evaluated whether the osmoregulatory active neutral amino acid glycine, which contributes to CV regulation via activation of sodium-dependent neutr
PMID 24760586

Japanese Journal

HNK-1 (human natural killer-1) glyco-epitope is essential for normal spine morphogenesis in developing hippocampal neurons

Morita Ippei,Kakuda Shinako,Takeuchi Yusuke,Kawasaki Toshisuke,Oka Shogo
Neuroscience 164(4), 1685-1694, 2009-12-29
… In this study, we showed that loss of the HNK-1 epitope resulted in an increase of filopodium-like immature spines and a decrease of mushroom-like mature spines in both the early postnatal mouse hippocampus and cultured hippocampal neurons. … However, HNK-1 had no influence on spine density or filopodium formation. …
NAID 120001741231

Morphological Change by Overexpression of D385A Dominant Negative Presenilin 1 in Human Neuroblastoma SH-SY5Y Cells

Tsuchiya Daiju,Kitamura Yoshihisa,Takata Kazuyuki [他],TANIGUCHI Takashi,UEMURA Kengo,MIKI Hiroaki,TAKENAWA Tadaomi,SHIMOHAMA Shun
Journal of pharmacological sciences 102(3), 354-358, 2006-11-20
… Moreover, filopodium-formation-related proteins were decreased only in cells overexpressing D385A PS1. …
NAID 10020345297