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生醫所校慶週專題演講活動，敬邀 中央研究院副院長 劉扶東院士【中央研究院生物醫學科學研究所特聘研究員兼所長】進行專題演講演講主題為：
Glycan recognition in inflammation and immunity
Abstract
Glycan-binding proteins (GBPs) function by recognizing glycans on the cell surfaces and extracellular matrices. Currently, C-type lectins (such as selectins), C-type lectin receptors (Clec), Siglecs, and galectins have gained more attention.
Galectins are a family of ��-galactoside-binding proteins, which differ from other glycan-binding proteins by not having a classical signal sequence and thus not being synthesized through the ER-Golgi pathway to be exocytosed. They are in fact present in the cytosol and can be translocated to the nucleus, although they can be secreted through an as yet undefined mechanism and exist in the extracellular space. Extracellularly, galectins can bind to and engage cell-surface glycans, thereby affecting a variety of cellular processes. However, importantly, they can function intracellularly in a glycan-independent fashion.
Galectin-7 is highly expressed in stratified epithelia, including epidermis, but is down-regulated in psoriasis. Using microarray and deep-sequencing analyses, we found galectin-7 positively and negatively regulates miR-203 and miR-146a expression, respectively. We demonstrated that galectin-7 i) suppresses keratinocyte proliferation through the JNK1-miR-203-p63 pathway; and ii) suppresses production of inflammatory mediators by keratinocytes through the miR-146a-MAPK/ERK pathway. These are intracellular functions.
A picture that has emerged recently is that galectins can bind to cytosolic glycans, when cells are infected by intracellular microbes. Specifically, galectins can accumulate around bacteria that have escaped from the phagosomes, through binding to host glycans on the membrane of ruptured phagosomes that initially contain the bacteria. Additional studies might establish the paradigm that the major and unique functions of galectins are linked to intracellular glycan recognition.
▲劉扶東院士專題演講
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