Cytoskeleton and Nucleotide Signaling in Glioma C6 Cells.

This chapter describes signaling pathways, stimulated by the P2Y nucleotide receptor (P2YR), that regulate cellular processes dependent on actin cytoskeleton dynamics in glioma C6 cells. P2YR coupled with G-proteins, in response to ATP or UTP, regulates the level of iphosphatidylinositol-4,5-bisphosphate (PIP) which modulates a variety of actin binding proteins and is involved in calcium response and activates Rac1 and RhoA proteins. The RhoA/ROCK signaling pathway plays an important role in contractile force generation needed for the assembly of stress fibers, focal adhesions and for tail retraction during cell migration.

[Watching dance of the molecules - CARS microscopy].

CARS (Coherent Anti-Stokes Raman Scattering) microscopy is an imaging method for living cells visualization as well as for food or cosmetics material analysis without the need for staining. The near infrared laser source generates the CARS signal - the characteristic intrinsic vibrational contrast of the molecules in a sample which is no longer caused by staining, but by the molecules themselves. It provides the benefit of a non-toxic, non-destructive and almost noninvasive method for sample imaging.

HAX-1: a novel p-body protein.

HAX-1, a multifunctional protein involved in the regulation of apoptosis, cell migration, and calcium homeostasis, binds the 3' untranslated region motifs of specific transcripts. This suggests that HAX-1 plays a role in post-transcriptional regulation, at the level of mRNA stability/transport or translation. In this study, we analyze in detail HAX-1 colocalization with processing bodies (P-bodies) and its dependence on mRNA availability.

[Nucleotide receptors and actin cytoskeleton dynamics].

Signaling cascades evoked by P2Y2 receptor plays an important role in the phenomena dependent on the actin cytoskeleton dynamics endocy-tosis, cell division, adhesion, intracellular transport and migration. P2Y2R coupled with G proteins, in response to ATP or UTP activates Rac1 and RhoA proteins important factors in actin cytoskeletal reorganization and regulates the level of phosphatidylinositol-4,5-bisphosphate (PIP2) that binds directly to a variety of actin regulatory proteins and modulates their function. The P2Y2 nucleotide receptor contains the integrin-binding domain enables it to interact selectively with α(v)β3 and α(v)β5 integrins and is required for G0-mediated Rac1 activation.

HAX-1 is a nucleocytoplasmic shuttling protein with a possible role in mRNA processing.

HAX-1 is a multi-functional protein that is involved in the regulation of apoptosis, cell motility and calcium homeostasis. It is also reported to bind RNA: it associates with structural motifs present in the 3' untranslated regions of at least two transcripts, but the functional significance of this binding remains unknown. Although HAX-1 has been detected in various cellular compartments, it is predominantly cytoplasmic.

Cytoskeleton and nucleotide signaling in glioma C6 cells.

This chapter describes signaling pathways stimulated by the P2Y(2) nucleotide receptor (P2Y(2)R), that regulate cellular processes dependent on actin cytoskeleton dynamics in glioma C6 cells. P2Y(2)R coupled with G-proteins, in response to ATP or UTP, regulates the level of phosphatidylinositol-4,5-bisphosphate (PIP(2)) which modulates a variety of actin binding proteins and is involved in calcium response and activates Rac1 and RhoA proteins. The RhoA/ROCK signaling pathway plays an important role in contractile force generation needed for the assembly of stress fibers, focal adhesions and for tail retraction during cell migration.

Is MLC phosphorylation essential for the recovery from ROCK inhibition in glioma C6 cells?

Inhibition of Rho-associated protein kinase (ROCK) activity in glioma C6 cells induces changes in actin cytoskeleton organization and cell morphology similar to those observed in other types of cells with inhibited RhoA/ROCK signaling pathway. We show that phosphorylation of myosin light chains (MLC) induced by P2Y₂ receptor stimulation in cells with blocked ROCK correlates in time with actin cytoskeleton reorganization, F-actin redistribution and stress fibers assembly followed by recovery of normal cell morphology. Presented results indicate that myosin light-chain kinase (MLCK) is responsible for the observed phosphorylation of MLC.

Folic acid-conjugated core/shell ZnS:Mn/ZnS quantum dots as targeted probes for two photon fluorescence imaging of cancer cells.

This work presents a novel approach to producing water soluble manganese-doped core/shell ZnS/ZnS quantum dots (ZnS:Mn/ZnS). The Mn-doped ZnS core was prepared through a nucleation doping strategy and a ZnS shell was grown on ZnS:Mn d-dots by decomposition of Zn(2+)-3-mercaptopropionic acid (MPA) complexes at 100 °C. It was found that the Mn2+(4)T1→6A1 fluorescence emission at ∼590 nm significantly increased after growth of the shell when the Mn2+ doping content was 4.

[Fluorescence lifetime imaging microscopy (FLIM) in biological and medical research].

Fluorescence lifetime imaging microscopy (FLIM) is a powerful tool for producing an image based on the differences in the exponential decay rate of the fluorescence from a fluorescent sample. This technique can provide information, not only concerning the localization of specific fluorophores, but also about the local fluorophore environment. It can be used in scanning confocal, multi-photon microscopes, or in wide-field microscopes and endoscopes.