Immunolocalization of a putative unconventional myosin on the surface of motile mitochondria in locust photoreceptors.
Light stimulation of locust (Schistocerca gregaria) photoreceptors results in an actin-dependent translocation of mitochondria towards the photoreceptive microvilli and an antagonistic movement of endoplasmic reticulum towards the cell body. Using immunocytochemical techniques, we have tried to identify myosin-like motors that may drive the light-induced organelle motility. A monoclonal antibody against the motor domain of Acanthamoeba myosin identifies a prominent 110-kDa protein on Western blots of locust retina. Cross-reactivity with two polyclonal anti-myosin antibodies and a monoclonal anti-myosin-I-antibody, together with ATP-dependent binding to actin filaments, provides evidence that the 110-kDa protein is an unconventional myosin. By indirect immunofluorescence, the 110-kDa protein has been localized to both photoreceptors and pigment cells within the retina. In the photoreceptor cells, the 110-kDa protein is bound to the surface of mitochondria. This putative unconventional myosin may thus be a motor protein involved in the light-induced translocation of mitochondria in photoreceptors.
Stürmer
K
K
Institut für Zoophysiologie und Zellbiologie, Universität Potsdam, Lennéstr. 7a, D-14471 Potsdam, Germany.
Baumann
O
O
D000199:Actins / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D003429:Cross Reactions; D003593:Cytoplasm / Q000378:metabolism; D019084:Fluorescent Antibody Technique, Indirect; D006110:Grasshoppers / Q000737:chemistry* / Q000648:ultrastructure; D015151:Immunoblotting; D007150:Immunohistochemistry; D008928:Mitochondria / Q000737:chemistry*; D009218:Myosins / Q000032:analysis* / Q000378:metabolism; D015388:Organelles / Q000737:chemistry; D017956:Photoreceptor Cells, Invertebrate / Q000737:chemistry* / Q000648:ultrastructure; D012160:Retina / Q000737:chemistry
D000199:Actins; D000255:Adenosine Triphosphate; D009218:Myosins