Motile areas of leech neurites are rich in microfilaments and two actin–binding proteins: gelsolin and profilin

Abstract

Cell motility is produced by changes in the dynamics and organization of actin ¢laments. The aim of the experiments described here was to test whether growing neurites contain two actin-binding proteins, gelsolin and pro¢lin, that regulate polymerization of actin and a¡ect non-neuronal cell motility. The distribution of gelsolin, pro¢lin and the micro¢laments was compared by immunocytochemistry of leech neurons growing in culture. We observed that micro¢laments are enriched in the peripheral motile areas of the neurites. Both gelsolin and pro¢lin are also concentrated in these regions. Gelsolin is abundant in ¢lopodia and is associated with single identi¢able micro¢lament bundles in lamellipodia. Pro¢lin is not prominent in ¢lopodia and shows a di¡use staining pattern in lamellipodia. The colocalization of gelsolin and pro¢lin in motile, micro¢lament-rich areas supports the hypothesis that they synergistically regulate the actin dynamics that underlie neurite growth.

Silencing profilin-1 inhibits endothelial cell proliferation, migration and cord morphogenesis

“…Since host-cell induced movement of pathogens is a molecular mimicry of actin polymerization at the leading edge of migrating cells, it is thought that one of Pfn1's function is to facilitate actin assembly during cell protrusion. This notion is further supported by several other studies demonstrating Pfn1's involvement in the formation of actin-based protrusive structures (Hajkova et al, 2000;Suetsugu et al, 1998;Suetsugu et al, 1999) as well as its preferential localization at the protrusive edge (Buss et al, 1992;Chou et al, 2002;Neely and Macaluso, 1997;Neuhoff et al, 2005). Given Pfn1's importance in cell migration and proliferation, it is thus intriguing that Pfn1 expression is conspicuously down-regulated in aggressive mammary and pancreatic carcinoma cells when compared with their normal counterparts (Gronborg et al, 2006;Janke et al, 2000).…”

Accelerators, Brakes, and Gears of Actin Dynamics in Dendritic Spines

“…An upregulation in gelsolin mRNA [331] and gelsolin protein levels [332] was found in the rat hippocampus following entorhinal deafferentation, suggesting that gelsolin may play a role in brain remodeling following hippocampal injury. Filopodia and lamellipodia are enriched with gelsolin [333, 334], and gelsolin knock-out mice exhibit slower filopodial retraction [335], further supporting the role of gelsolin in cell-protrusive activities. Gelsolin knock-out mice exhibit increased Ca 2+ influx following glutamate exposure [336] and fail to display an NMDA receptor-dependent decrease in the actin turnover rate [337].…”

Interaction of leech neurons with topographical gratings: comparison with rodent and human neuronal lines and primary cells

“…Invertebrates, for example leeches, have proved to be useful models for studying neuronal dynamics [34][35][36]. The simple nervous system and cellular accessibility, together with the large size and the single neuron identifiability in vivo and in vitro, are some of the invertebrate advantages that allowed us to improve the knowledge about evolutionarily conserved neuronal mechanisms [37].…”