GELFAND, Vladimir I.

Department of Cell and Structural Biology
Ph. D./ D. Sc. (1975) Moscow State University

     Research Topics   

     Research Interest

   Eukaryotic cells employ motor proteins, enzymes capable of converting ATP hydrolysis directly into kinetic force, to transport cargo within the cytoplasm and to drive the cellular machinery responsible for cellular migration. Intracellular cargoes such as organelles rely upon motor proteins for their proper distributions within the cytoplasm during processes such as axonal transport, endocytosis, and secretion. During mitosis, chromosomes are distributed to the two daughter cells by the coordinated activities of motors, as well. Changes of cell shape, such as those which occur during muscle contraction and embryonic development, are also powered my motor proteins. Although many different molecular motors have been identified, the roles which they play and the mechanisms by which they are regulated remain fundamental questions confronting cell biologists. 

   The research in our laboratory has focused on understanding the molecular basis of motor protein regulation. The system which we employ is a Xenopus melanophore cell line. These cells possess hundreds of pigmented organelles, called melanosomes, which are either transported centripetally to aggregate at the center of the cell or centrifugally to disperse throughout the volume of the cytoplasm. In nature, melanophores present in the skin of fish and frogs undergo this cycle of aggregation and dispersion to confer the ability to change color to the animal. Pigment dispersal causes the animal's skin to darken, while pigment aggregation produces lightening. These cells are a classically studied system for intracellular motility, and it has previously been shown that two classes of motor proteins, the kinesins and dyneins, mediate melanosome transport by carrying them along the cells' radial microtubule cytoskeleton. In culture, pigment aggregation and dispersion may be induced by the application of hormones, thus providing large quantities of melanophores in either the dispersed or aggregated states which are amenable to biochemical study. These cells represent the most dramatic example of intracellular transport in nature; information gleaned from the study of organelle transport in melanophores will provide important insight as to how motors are regulated in other systems, as well.

     

   Key Words   Cytoskeleton, Motor proteins, Kinesin, Dynein, Myosin, Tissue Culture, Microscopy, Regulation, Kinases, Phosphatases

   Current Research Funding   NSF, NIH

BTC Members