Endocytotic Cycling of PM Proteins - 首都师范大学精品 ….ppt

Endocytotic Cycling of PM Proteins Junxia An Xihua Chen Summarize Comparison of plasma membrane localization in polarized animal and plant cells. Types of endosytosis Endosomal Cycling In Animals: An Overveiw Protein Components of Endocytotic Cycling Mechanisms Introduction Eukaryotic cell respond to external signals by altering(改变) transcriptional(转录) output and regulating the abundance(含量) and distribution(分布) of PM proteins that comprise the functional interface with the external environment . Animals (Yeast) PM protein removal and recompartmentalization is regulated by endocytosis and endocytotic cycling. Plants PM localization of the PIN1 auxin efflux carrier complex and the KAT1 potassium channel are dynamically regulated has intensified efforts to conclusively demonstrate endocytotic recycling in plants. Endosomal Cycling In Animals:An Overveiw Endocytosis: Take up extracellular substances and/or internalize PM proteins for transport to endosomes. comprise Highly dynamic structures Helps maintain homeostatic regulation Endosomes PM proteins Target into the lysosome/vacuole for degradation or recycled back to cell surface.(M6P) Mammalian endocytosis regylates multiple physiological processes Types of endocytosis Receptor-mediated endocytosis (受体介导) Clathrin-dependent endocytosis (网格蛋白介导) Clathrin-independent endocytosis (非网格蛋白介导) Caveolae/lipid raft-mediated endocytosis (晶格镶嵌型脂筏) Fluid-phase endocytosis (液相内吞) Phagocytosis (吞噬) Receptor-mediated endocytosis RME (受体介导的内吞作用) Ligand bind to a PM receptor (uptake proteins or protein complexes) from the cell surface, then internalized in the cell. Clathrin-mediated RME(网格蛋白介导的受体介导内吞作用) Steps: Ligands bound to their receptors (AP2 adaptor complex; AP-180; ARF6GTPase) Clustering(聚集) in clathrin-coat Destined for degradation in lysosomes (M6p) Clathrin-independent processes Caveolae/lipid raft-mediated endocytosis Fluid-phase endocytosis Phagocytosis (吞噬) Early endosomes/Sorting endo