Kinesin is responsible for centrifugal movement of pigment granules in melanophores

Abstract

Kinesin is a mechanochemical ATPase that induces translocation of latex beads along microtubules and microtubule gliding on a glass surface. This protein is thought to be a motor for the movement of membranous organelles in cells. Recently Hollenbeck and Swanson [Hollenbeck, P. J. & Swanson, J. A. (1990) Nature (London) 346, 864-866] showed that kinesin is involved in the positioning of tubular lysosomes in macrophages. However, the role of this protein in the movement of organelles was not yet clear. We used a polyclonal antibody against the kinesin heavy chain that inhibited kinesin-dependent microtubule gliding in vitro to study the role of kinesin in the movement of pigment granules in melanophores of the teleost black tetra (Gymnocorymbus ternetzi). Microinjection of the antibody into cultured melanophores did not produce any specific effect on the aggregation of pigment granules in melanophores, but it did result in a strong dose-dependent inhibition of the dispersion. Immunoblotting of melanophore extracts showed that the kinesin antibody reacted in these cells with a single protein component with a molecular mass of 135 kDa. Thus, kinesin is responsible for the movement of pigment granules from the center to the periphery of the melanophore.