Talin dynamics in living microinjected nonmuscle cells

Area of Science:

• Cell Biology
• Molecular Biology
• Biochemistry

Background:

• Talin is an adhesion plaque protein crucial for linking the actin cytoskeleton to the cell membrane.
• Understanding talin's dynamic role in nonmuscle cells requires direct visualization in living systems.

Purpose of the Study:

• To develop and characterize a fluorescent analog of talin for microinjection into living cells.
• To investigate the dynamic role and localization of talin in nonmuscle cell adhesion plaques and stress fiber anchoring.

Main Methods:

• Covalent labeling of purified chicken gizzard talin with lissamine rhodamine B sulfonyl chloride.
• Purification of fluorescent talin using Sephadex G-25 and DEAE-cellulose chromatography.
• Microinjection of fluorescent talin into living PtK2 epithelial cells and observation via computer-enhanced video microscopy.

Main Results:

• Fluorescent talin localized to adhesion plaques, membrane ruffles, microspikes, and polygonal networks, confirming its presence in key cellular structures.
• Dynamic changes in adhesion plaque shape, position, appearance, growth, and dissolution were observed in living cells.
• Adhesion plaques disassembled during mitosis and reformed upon cell spreading, with talin localization altered by DMSO-induced stress fiber disassembly.

Conclusions:

• This study provides the first direct visualization of talin's dynamic role in living nonmuscle cells.
• Talin is essential for the dynamic anchoring of actin stress fibers to the cell membrane and participates in adhesion plaque remodeling.
• Talin localization is sensitive to cytoskeletal organization and cell cycle progression.