Anti-actin antibodies generated against profilin:actin distinguish between non-filamentous and filamentous actin, and label cultured cells in a dotted pattern

Profilin induces lamellipodia by growth factor independent mechanism

“…A similar distribution has been reported previously: profilin appears enriched in areas of membrane ruffling (46,56). In more detail, in PtK2 and BHK-21 cells, profilin was enriched at peripheral areas of ruffling activity distributed in fine vesicular structures (punctae) or forming a reticular network identified as the network of profilin:actin (33,34,57). The recombinant protein, soon after the addition, was found in vesicle-like structures at the lamellipodia membrane, probably associated with the process of macropynocytosis.…”

Conformation-specific antibodies reveal distinct actin structures in the nucleus and the cytoplasm

“…Unlike other actin antibodies, such as 2G2 (Gonsior et al, 1999 and Fig. 4) and a recently published polyclonal antibody raised in chicken (Grenklo et al, 2004) which exhibit a Wlamentous staining pattern after methanol treatment, 1C7 did not bind to Wlamentous actin under these conditions. Even a mild detergent extraction prior to Wxation did not reveal a Wlamentous staining pattern.…”

“…Actin has been characterized as an abundant protein with a plethora of diverse functions in the cytoplasm, but it has also been described as a component of the nucleus for quite some time (Bremer et al, 1981;Gonsior et al, 1999;Grenklo et al, 2004;Jockusch et al, 1974;Scheer et al, 1984). The failure to detect bona Wde Wlaments that stain with phalloidin in nuclei conferred to many that nuclear actin simply reXects a contamination from the cytoplasm.…”

Profilin as a dual regulator of actin and microtubule dynamics

“…Antibodies against profilin generate a dot-like pattern and enrichment at the leading cell edge and perinuclear region that might be compatible with a fraction of the protein being colocalized with microtubules (Buss, Temmgrove, Henning, & Jockusch, 1992;Li, Grenklo, Higgins, & Karlsson, 2008;Mayboroda, Schluter, & Jockusch, 1997;Skare, Kreivi, Bergstrom, & Karlsson, 2003). Later, it has been demonstrated that, in fact, profilin partially codistributes with microtubules in human fibroblasts (Grenklo, Johansson, Bertilson, & Karlsson, 2004) which was recently F I G U R E 2 Actin treadmilling is synergistically powered by profilin and ADF/cofilin proteins. ADF/cofilin (blue circles) loads cooperatively onto microfilament sides enriched of adenosine diphosphate (ADP)-actin (light gray G-actin) leading to F-actin severing and disassembly at pointed ends.…”

“…These findings led to the suggestion that complexes of actin-bound profilin might be transported along microtubules towards cellular regions where active actin polymerization requires an increased concentration of G-actin (Grenklo et al, 2004), as occurs in the case of other cytoskeleton components such as intermediary filaments (Chou et al, 2007). In contrast to previous findings showing lack of tubulin binding to a Pfn2 affinity column (Witke et al, 1998), recent results found that glutathione S-transferase (GST)-Pfn2b binds tubulin in non-neuronal cells and that green fluorescent portein (GFP)-Pfn2b is recruited to spindles and asters during mitosis in HeLa cells (Di Nardo, Gareus, Kwiatkowski, & Witke, 2000).…”