>Gel-like network Actin filaments are often nucleated at the plasma membrane. The highest density of actin filaments is at the cell periphery forming cell cortex. filamin dimer 50 Filamin cross-links actin filaments into a three-dimensional network with the physical properties of a gel. Loss of filamin causes abnormal cell motility
➢Gel-like network Actin filaments are often nucleated at the plasma membrane. The highest density of actin filaments is at the cell periphery forming cell cortex. Filamin cross-links actin filaments into a three-dimensional network with the physical properties of a gel. Loss of filamin causes abnormal cell motility
E。 Functions of Mfs (1)Maintain cell,s shape and enforce PM asma membrane Glycophorin Band 3 dimer Band 4.1 Ar nkyrin pectin tetramer
E. Functions of MFs (1) Maintain cell’s shape and enforce PM
CELL ATTAOHMENT TO EXTRACELLULAR MATAD CYTosol EXTRACELLULAR MATRDC Figure 10-75 A model for how integrins in the plasma membrane connect intracellular actin filaments to the extracellular matrix at a focal contact. The formation of a focal contact occurs when the binding of matrix glycoproteins(such as fibronectin) on the outside of the cell causes the integrin molecules to cluster at the contact site, as illustrated schematically in(A). A possible arrangement of some of the intracellular attachment proteins that mediate the linkage between an integrin and actin filaments is shown in B)
Figure 10-75 A model for how integrins in the plasma membrane connect intracellular actin filaments to the extracellular matrix at a focal contact. The formation of a focal contact occurs when the binding of matrix glycoproteins (such as fibronectin) on the outside of the cell causes the integrin molecules to cluster at the contact site, as illustrated schematically in (A). A possible arrangement of some of the intracellular attachment proteins that mediate the linkage between an integrin and actin filaments is shown in (B)
(2)Cell migration(Fibroblast et al) 4 Platelet activation is a controlled sequence of actin filament severing, uncapping, elongation, recapping, and cross-linking. fimbrin, (r-aciinin filamin activated gelsolin BUNDLING AND 后 SIGNAL ROSS- LINKING OF SLOW RISE IN CTIN FILAMENTS PIP, ACTIVATES AND MYOSIN GELSOLIN CONTRACTION monomers bound to profili atin filaments capped severed actin filaments gelsolin and capping cy capping protein in capped mostly by Ca-activated protein removed, and rapi activated platelet unactivated blood gelsolin and some capping actin filament growth spreads out, attaches to protein from many short fragments blood clot, and contracts 2 um
(2) Cell migration (Fibroblast et al) ❖Platelet activation is a controlled sequence of actin filament severing,uncapping, elongation,recapping, and cross-linking
(3) Microvillus: Support the projecting membrane of intestinal epithelial cells plus end of actin filament plasma membrane lateral sidearm (myosin crosslink (villin, fimbrin) I um
(3) Microvillus: Support the projecting membrane of intestinal epithelial cells