High content analysis of apical versus basolateral trafficking

点击翻译按钮获取中文摘要

Proteins are required to be sent to various cellular compartments in order for those distinct compartments to function efficiently. Small structures called vesicles mediate the sorting and trafficking of proteins. This current research program aims to elucidate how vesicles mediate the sorting and intracellular trafficking to the plasma membrane of polarized cells. Aquaporins are water permeable membrane channels found on the outer membrane of cells. Mammalian cells express 13 aquaporins, with aquaporins-0, -1, -2, -4, -5, -6 and -8 being permeable only to water, while aquaporins-3, -7, -9 and -10 are also permeable to small molecules such as urea and glycerol. Within cells, aquaporins can localize to specific membrane domains. For example, aquaporin-4 (AQP4) traffics and is localized to the basolateral membrane (the side and bottom of cells), while AQP5 is found on the apical plasma membrane (top of the cell). Although AQP expression is restricted, the molecular mechanisms that regulate this trafficking have not been fully elucidated. We have recently shown AQP4 vesicles are actively transported in cells, but to our surprise, found that vesicles are not directed towards their destination. Instead, we found that, vesicle dynamics in non-polarized (cells that do not have specific sides, bottom or top) and polarized cells was similar. This suggested that trafficking vesicles “sample” membrane targets and fuse to the appropriate target membrane to localize proteins, a significant shift away from current thinking.