Localization of selenium-binding protein at the tips of rapidly extending protrusions

Abstract

Cell protrusive motility underlies cell fundamental biological processes such as cell growth, locomotion, and migration. Here I showed that selenium-binding protein (SBP) was exclusively located at the leading edges of rapidly growing protrusions in newly plated T98G glioma cells, and at the growing tips of the neurites in SH-SY5Y neuroblastoma cells. Double staining by anti-SBP antibody and deoxyribonuclease (DNase I) that labels monomeric G-actin or phalloidin that labels filamentous F-actin showed that the SBP-positive area was overstained by DNase I but, surprisingly, was not stained by phalloidin. When the cells were incubated with chemicals which block actin polymerization or activity of phosphatidylinositol 3-kinase, recruitment of SBP and G-actin at the cell margin was still observed, showing that their recruitment precedes actin polymerization. Taken together, I suggest that SBP may be involved in the initial sequential events in rapid cell outgrowth, such as determining direction of cell outgrowth and recruitment of actin monomer.

Novel interaction of selenium-binding protein with glyceraldehyde-3-phosphate dehydrogenase and fructose-bisphosphate aldolase of Arabidopsis thaliana

“…Homologues of SBP exist in many eukaryotic and prokaryotic organisms, sharing a significantly conserved amino acid sequence, comparable to that of the histone (Thatcher and Gorovsky 1994) or actin (Egelman 2003) protein families. Although the physiological function of SBP remains unknown, studies based primarily on animal systems associate SBP with the inhibition of cell proliferation and anti-carcinogenic growth regulation (Lanfear et al 1993;Yang and Sytkowski 1998;Chen et al 2004), with acetaminophen-induced hepatotoxicity (Bartolone et al 1992;Pumford et al 1992;Lanfear et al 1993;Qiu et al 1998;Ishida et al 2004), interaction with other minerals (Jamba et al 1997;She et al 2003), detoxification (Ishii et al 1996a, b;Ishida et al 1998Ishida et al , 1999, intra-Golgi protein transport (Porat et al 2000), peroxisome proliferation (Giometti et al 2000;Chu et al 2004), senescence (Cho et al 2003), rapid cell outgrowth and motility (Miyaguchi 2004) and oxidative stress response Gracey et al 2001;Casey et al 2002;Fajardo et al 2004).…”

The utility of SELENBP1 gene expression as a biomarker for major psychotic disorders: Replication in schizophrenia and extension to bipolar disorder with psychosis

“…For example, using microarray analysis we recently demonstrated that the expression of the selenium binding protein 1 gene (SELENBP1) was increased in the blood and brain of patients with schizophrenia [Glatt et al, 2005], a finding that we confirmed in the blood using quantitative realtime PCR (QPCR). Although the functional role of SELENBP1 is not well understood in the brain, selenium-binding proteins have been shown to co-localize with g-actin at the growing tips of SY5Y neuroblastoma cells [Miyaguchi, 2004], which indicates the potential for SELENBP1 to be associated with the growth and remodeling of neurites. These results are of interest in light of alterations in dendritic and synaptic proteins noted in both bipolar disorder and schizophrenia [Harrison, 1999[Harrison, , 2002.…”

Expression of selenium‐binding protein 1 characterizes intestinal cell maturation and predicts survival for patients with colorectal cancer

“…The expression of SBP1 is high in the heart and intermediate in the liver, lung, kidney, and intestine. It has been suggested that SBP1 facilitates intracellular transport of selenium in the late stages of intra-Golgi protein transport [11] and protrusive cell motility [12]. Recent reports demonstrated that SBP1 protein is downregulated in several epithelial tumors including lung [8], prostate [13,14], stomach [15], colorectal [6,16], and ovarian cancer [10].…”