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Microfilaments

Microfilaments. Microtubules Microfilaments. Text and image sources are included using the notes function of this file. minus. Microfilament (thin filament) structure. G-actin monomer. ATP. --- 7-8nm. 25nm. plus. G-actin (42-43kD; 375 aas). (minus)

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Microfilaments

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  1. Microfilaments MicrotubulesMicrofilaments Text and image sources are included using the notes function of this file

  2. minus Microfilament(thin filament) structure G-actin monomer ATP --- 7-8nm 25nm plus

  3. G-actin (42-43kD; 375 aas) (minus) (plus) Changes upon hydrolysis Animation

  4. Intrafilament contacts

  5. Polarity of assembly(in vitro assay) Video + G-actin, ATP Red arrow = minus end Green arrow = initial plus end Bulls-eye = contact point on surface + -

  6. + S1 Decoration -

  7. S1 decoration reveals microfilament polarities in situ a. Cytoplasm (mixed polarities) b. Stress fibers (bundled mixed polarities) c. Lamellipodia (uniform polarity, points in)

  8. The Angel of Death Mushroom Amanita phalloides Phalloidin

  9. Cells labeled with Phalloidin (F-actin) and DNase I (G-actin)

  10. Actin Binding Proteins (ABPs) modulate architectures “. . . the actin cytoskeleton is a complex three-dimensional molecular jigsaw puzzle” - Tom Pollard

  11. Profilin is involved in ATP recharge profilin

  12. Cofilinweakens subunit interactionsby structuralintrogression

  13. Alpha-actinin crosslinks microfilaments

  14. Actin subunit Amoeboid motility uses Gelsolin Gelsolin (partial structure) in presence of Ca++ Video

  15. F-actinmotilities Composite time lapse segments

  16. Actin dynamics at the leading edge GFP::actin in a tissue culture cell 2 time-lapse video sequences

  17. Axonal growth cones Video GFP-actin dynamics Video Microtubules are excluded from the periphery Cell microinjected with fluorescent tubulin to label microtubules

  18. Treadmilling within the lamellipodium Video

  19. Keratocyte motility Video

  20. Arp2/3 immunolocalization Branching out on the family tree: the Arp2/3 complex plus 70o minus Nucleation Promoting Coronin Factors (NPFs) WASp/SCAR/Wave

  21. The Actin Family Tree

  22. Formin those long filaments - + G-actin monomer

  23. WASp SCAR Assembly Cycles ATP translation Formin Arp2/3 VASp Dynamic F- actinADP microfilament CCT G-actinATP ADP (exchange) ATP PIP2 Profilin Stabilizing ABPs WASp VASp Thymosin Stable F-actin microfilament G-actinADP Severin Gelsolin

  24. F-actin And VASp NPF: VASp(vasodilator stimulated phosphoprotein) Video

  25. Signal transduction links G-proteins WASp WASp*P PIPkinase MLCK Cdc42 Rac Rho Filipodia Localized Initiation Lamellipodia Frontal Initiation Increased Turnover Stress fibers Form and Tension Arp2/3 PIP PIP2 Myosin Formin

  26. Stress fibers distribute forces Arrows highlight microtubules adjacent to the stress fiber bundle

  27. Getting in shape

  28. Neutrophil motility Video

  29. Microvilli

  30. Anchored in the terminal web

  31. Stereocilia MyoVIIa is involved in Ca++ regulated adaptation

  32. Act’in Up Video Listeria monocytogenes moving in PtK2 cells

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