Microtubule (MT) substrates are required in the study of a wide range of Microtubule Associated Proteins (MAPs). The formation of MTs in vitro is a complex
process in which the length and final polymer mass of MTs is greatly affected by experimental conditions, including temperature, tubulin purity, tubulin concentration, timing of the polymerization reaction, timing of paclitaxel addition and buffer conditions. Scientists at Cytoskeleton, Inc. have developed a patented method for MT production and lyophilization that ensures highly reproducible MTs (2 μm average length). Pre-formed microtubules (Cat. # MT001) provide an extremely convenient way to perform assays requiring microtubules as a substrate. Microtubules are supplied as a stable lyophilized powder, simply resuspend and use. Uses for pre-formed stabilized microtubules include:

• Substrate for discovery and characterization of microtubule binding proteins (MAPs)
• Substrate for activation of kinesin ATPase
• Determination of IC50s for kinesin inhibitors
• Used in Cytoskeleton, Inc’s kinesin ELIPA and end point ATPase assays (BK060 & BK053)
• Ideal for HTS applications (inquire for bulk rates). Corporate references on request.

Pre-formed actin filaments (PAFs) serve as a substrate for myosin motor proteins. Myosin motor proteins orchestrate a wide range of kinetic events within a cell. They have been shown to move cargoes such as vesicles along actin filament tracks.
PAFs are supplied as a lyophilized powder. PAFs have been prepared from rabbit skeletal muscle actin protein that is greater than 99% pure (Cat. # AKL99). These stringently quality controlled filaments provide highly reliable and reproducible results in assays that require actin filament substrates. The average filament length in this product is 8 µm. Using these PAFs in assays depending on filaments gives very reproducible results. In an actin filament activated myosin ATPase assay (see Fig. bellow), the CV between samples (Vmax) was less than 5% and the CV of Vmax between assays using different batches of AKF99 was less than 8%.