Monkey Kidney Cells with mEmerald-Tubulin
Most eukaryotic cells contain three different basic types of cytoskeletal filaments, one of which is microtubules. Each cytoskeletal filament variety functions in its own characteristic manner in addition to working together to maintain the cytoskeletal integrity of a cell. Microtubules play a key role in the regulation of intracellular molecule transport and positioning membrane-bound organelles. Two closely related globular subunits, alpha-tubulin and beta-tubulin, are the fundamental components of microtubules.
The basic structural subunits of microtubules are composed of the protein Tubulin. Every tubulin subunit is a heterodimer comprised of two globular proteins: alpha-tubulin and beta-tubulin components connected by noncovalent bonds. These proteins, which only occur in this network, each provide a binding site for one guanosine triphosphate (GTP) molecule.
Microtubules were visualized in the selected digital video sequence with the green fluorescent protein mEmerald fused to tubulin. mEmerald is a variant of EGFP, an enhanced Aequorea derivative. In addition to the S65T and F64L mutations found in EGFP, mEmerald features four additional point mutations that render it brighter and more photostable than its predecessor.