Differential regulation of dynein-driven melanosome movement.
Cytoplasmic dyneins are multisubunit minus-end-directed microtubule motors. Different isoforms of dynein are thought to provide a means for independent movement of different organelles. We investigated the differential regulation of dynein-driven transport of pigment organelles (melanosomes) in Xenopus melanophores. Aggregation of melanosomes to the cell center does not change the localization of mitochondria, nor does dispersion of melanosomes cause a change in the perinuclear localization of the Golgi complex, indicating that melanosomes bear a dedicated form of dynein. We examined the subcellular fractionation behavior of dynein light intermediate chains (LIC) and identified at least three forms immunologically, only one of which fractionated with melanosomes. Melanosome aggregation was specifically blocked after injection of an antibody recognizing this LIC. Our data indicate that melanosome-associated dynein is regulated independently of bulk cytoplasmic dynein and involves a subfraction of dynein with a distinct subunit composition.
Reilein
Amy R
AR
Department of Cell and Structural Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
Serpinskaya
Anna S
AS
Karcher
Ryan L
RL
Dujardin
Denis L
DL
Vallee
Richard B
RB
Gelfand
Vladimir I
VI
D000818:Animals; D015153:Blotting, Western; D002478:Cells, Cultured; D003593:Cytoplasm / Q000737:chemistry; D004398:Dyneins / Q000032:analysis / Q000276:immunology / Q000378:metabolism*; D008547:Melanophores / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D020460:Melanosomes / Q000737:chemistry / Q000378:metabolism*; D008550:Melatonin / Q000494:pharmacology; D009068:Movement; D021122:Protein Subunits; D014981:Xenopus
D021122:Protein Subunits; D004398:Dyneins; D008550:Melatonin