Cytoplasmic Dynein and Cell Polarity
Cytoplasmic Dynein Mediated Directional Translocation and Cell Polarity
Cytoplasmic dynein is the multisubunit protein complex involved in a wide range of microtubule-based intracellular movements. One challenge is to understand how a cell coordinates all aspects of dynein function by coordinately regulating its cargo selection and binding/release of cargoes in a timely and spatially-coordinated manner.
Our lab previously showed that a light chain subunit of cytoplasmic dynein,Tctex-1, can serve as a linker that mediates the interaction between cargo and dynein complex. Specifically, Tctex-1 docks its cargo, rhodopsin, to the dynein motor and, hence, allows rhodopsin vesicles to travel on microtubules.
Our data also show that Tctex-1- and dynein- mediated activity is essential for the apical transport of rhodopsin in polarized epithelia. The "apical rhodopsin delivery" paradigm allows us to further investigate the mechanism underlying the cargo selectivity of the dynein motor and the mechanism regulating the assembly (and disassembly) between dynein complexes and cargoes. Our studies have provided direct evidence showing that cytoplasmic dynein function can be regulated by its subunit composition. In addition, dynein complex disassembles to release cargo via specific phosphorylation of Tctex-1, and this process is critical for the apical delivery of membrane cargoes.
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