Kinesin and Myosin Travel Along Molecular Rails Audra Amasino, Dianna Amasino, Re-I Chin, Yuting Deng, Gabriela Farfan, Axel Glaubitz, Samuel Huang, Jessie Lee, Adeyinka Lesi, Linus Marco, Yaoli Pu, JunYao Song, Peter Vander Velden, Min Yoo Advisor: Basudeb Bhattacharyya Associate Research Specialist University of Wisconsin, Madison, WI 53706 Mentors: Dr. David Nelson, Professor and Steve Goth, Undergraduate Department of Biochemistry, University of Wisconsin, Madison, WI 53706

Abstract Diseases Kinesin and myosin are motor proteins (driven by ATP) that Kinesin Myosin Myosin walk along molecular rails in order to transport molecular cargo within cells; kinesin moves along microtubules, myosin Hypertrophic Cardiomyopathy- A condition in which the heart moves along microfilaments of actin. Their cargos include muscles thicken because the heart is trying to make up for the other proteins, membrane vesicles, and organelles. Myosin decreased pumping that results from defective myosin. The also produces the contraction of muscle cells. Although they heart will eventually grow to an abnormally large size, and have similar functions, the binding sites, theATPase sites, symptoms such as shortness of breath, chest pain, palpitation, and the cargo binding sites differ. There are many types of light-headedness, and blackouts may occur. Some complications kinesin and myosin throughout the body that vary in load include irregular heartbeat, heart block, and sudden death. (bound to their cables) and direction of motion. Kinesin is Presently there is no cure, but there are treatments that help to composed of two identical “feet.” attached to a cable, that relieve symptoms. walk using a hand-over-hand motion. Myosin is a string of •Muscle myosin proteins work connected feet that moves by lifting one foot, planting it •Attaches to microtubules •Movement is processive farther down along the microfilament, pulling its cable together to perform their function •Use ATP to attach to surface •Structure: one or two heavy chains forward, then lifting a foot up again and repeating the motion. •Uses switches to faciliate conformation bound to several light chains, which changes •One kinesin protein acts alone. form a protein with a head, neck and •Structure: two large globular heads, •Both are motor proteins, which use tail domain. Introduction one central coiled region, and a light- ATP for energy •Crawls using step- by- step, chain region (tail), which connects the Movement is a key strategy for survival. For example, certain inchworm movement. Its head kinesin to the intracellular component • They transport domain pulls the actin to cause animals in the desert combat heat by moving to the shade, (cargo) cargo within a cell muscle cells to compress Rigor Mortis-Latin for “Stiffness of Death,” is the condition •Crawls hand-over -hand along controlling the environment in which they inhabit. The basis •Attaches to actin that occurs several hours after a person or animal dies. The a microtubule, using its two of such movement comes from muscle contractions. These, in heads, like feet, to step forward •Size ~ 10 to 40 nanometers muscles stiffen because there is no more ATP to fuel the turn, originate from the sliding of myosin against actin •Size ~ 50 nanometers alternating binding and release of myosin to microfilaments. filaments in sarcomeres. The mechanical motion of the Instead, myosin remains in firm contact with microfilaments, myosin heads derives from chemical energy, stored in ATP. locking the muscles in one position. Sarcomere Figure 4. Similarities and Differences between Kinesin and Myosin For both models, the orange helix represents the start of the “arm” or “leg” that does the pulling work. ADP is shown in CPK and important amino acid sidechains that facilitate binding are shown in purple. The carboxyl terminus is identified in red and the amino terminus, blue. Kinesin Some viruses, such as smallpox and herpes, use kinesin to move Actin Myosin within an infected cell. Withoutkinesin, it would take a herpes virus 231 years to travel 1 cm by the process of diffusion. Charcot-Marie-Tooth Disease-disease in the nerve cells that prevents the kinesin from moving mitochondria and other Figure 1. Structure and organization of muscle, proteins to the end of the axon, starving it of energy, making i t from tissue to fiber, to sarcomere and actin/myosin. impossible to relay nerve impulses.

QuickTime™ and a High arches, and hammer TIFF (LZW) decompressor On a smaller level inside the cell, movement is required for are needed to see this picture. toes are characteristics of transportation of proteins, membrane vesicles, and organelles CMT Disease. in order to induce chemical reactions. Such actions are facilitated by kinesin, which walk along the tubulin surface,

pulling molecular cargo behind them.Microtubules Like myosin,kinesin Conclusions uses ATP as an energy source. Kinesin • Myosin and kinesin are necessary for contraction of muscles and intracellular transportation • Both convert ATP to ADP to cause cyclic structural changes that generate movement • Kinesin moves in a hand-over-hand motion, while myosin Time lapse images of kinesin (left) and myosin (right) as they travel along their respective “rails”, microtubules and microfilaments. moves in a step-by-step inchworm motion. Figure 2. Microtubules in a cell and kinesin • Both move on tracks: kinesin on microtubules, myosin on Twelve tubulinsubunits of the microtubule (bottom of left panel) show a part of the surface on which kinesin, actin filaments. that walks along it the tubulin fiber. shown here in three successive positions, “walks” from right toleft. In the right panel, myosin (green and yellow) • Certain diseases and conditions are caused by dysfunction of walks along the actin filament (blue), leaving “footprints” (red) at each point of contact with the microfilament. myosin and kinesin Myosin and kinesin are part of a class of motor proteins that ATP powers the motion of bothkinesin and myosin. In each case there is a cycle of structural changes in the motor function in intercellular and intracellular activities– muscle protein as ATP first binds to the protein, then is broken down t o ADP and Pi, then Pi leaves. As the motor proteins contraction, organelle movement, cell locomotion, signal undergo these structural changes, they move along their rails. Kinesin, with two connected motor units, has a Acknowledgements relaying, and cytoplasmic streaming. Like trucks, the “hand-over-hand” motion, while myosin, with many connected motor units , slides along the microfilament like an proteins tow their shipments and travel across tracks of fibers. inchworm or a centipede. We would like to thank MSOE for giving us the opportunity to The fuel for their movements, or “gasoline”, is ATP. participate in this program and for producing our model using the rapid-prototyping technology. We also want to thank our mentor Dr. Dave Nelson, our advisor Basudeb Bhattacharyya, and Steve Goth for all their help and support. UW has been very generous in opening their facilities to the West High SMART team.

Figure 3. Motor Proteins are the “trucks” of the cell