Endocytosis is a cellular process in which substances are brought into the cell. The material to be internalized is surrounded by an area of cell membrane, which then buds off inside the cell to form a vesicle containing the ingested materials. Endocytosis includes pinocytosis and phagocytosis. It is a form of active transport.
The Golgi apparatus, also known as the Golgi complex, Golgi body, or simply the Golgi, is an organelle found in most eukaryotic cells. Part of the endomembrane system in the cytoplasm, it packages proteins into membrane-bound vesicles inside the cell before the vesicles are sent to their destination. It resides at the intersection of the secretory, lysosomal, and endocytic pathways. It is of particular importance in processing proteins for secretion, containing a set of glycosylation enzymes that attach various sugar monomers to proteins as the proteins move through the apparatus.
In cell biology, a vesicle is a structure within or outside a cell, consisting of liquid or cytoplasm enclosed by a lipid bilayer. Vesicles form naturally during the processes of secretion (exocytosis), uptake (endocytosis), and the transport of materials within the plasma membrane. Alternatively, they may be prepared artificially, in which case they are called liposomes. If there is only one phospholipid bilayer, the vesicles are called unilamellar liposomes; otherwise they are called multilamellar liposomes. The membrane enclosing the vesicle is also a lamellar phase, similar to that of the plasma membrane, and intracellular vesicles can fuse with the plasma membrane to release their contents outside the cell. Vesicles can also fuse with other organelles within the cell. A vesicle released from the cell is known as an extracellular vesicle.
Endosomes are a collection of intracellular sorting organelles in eukaryotic cells. They are parts of the endocytic membrane transport pathway originating from the trans Golgi network. Molecules or ligands internalized from the plasma membrane can follow this pathway all the way to lysosomes for degradation or can be recycled back to the cell membrane in the endocytic cycle. Molecules are also transported to endosomes from the trans Golgi network and either continue to lysosomes or recycle back to the Golgi apparatus.
The Rab family of proteins is a member of the Ras superfamily of small G proteins. Approximately 70 types of Rabs have now been identified in humans. Rab proteins generally possess a GTPase fold, which consists of a six-stranded beta sheet which is flanked by five alpha helices. Rab GTPases regulate many steps of membrane trafficking, including vesicle formation, vesicle movement along actin and tubulin networks, and membrane fusion. These processes make up the route through which cell surface proteins are trafficked from the Golgi to the plasma membrane and are recycled. Surface protein recycling returns proteins to the surface whose function involves carrying another protein or substance inside the cell, such as the transferrin receptor, or serves as a means of regulating the number of a certain type of protein molecules on the surface.
Ras-related protein Rab-5A is a protein that in humans is encoded by the RAB5A gene.
Ras-related protein Rab-7a is a protein that in humans is encoded by the RAB7A gene.
Ras-related protein Rab-8A is a protein that in humans is encoded by the RAB8A gene.
Ras-related protein Rab-9A is a protein that in humans is encoded by the RAB9A gene.
Ras-related protein Rab-11B is a protein that in humans is encoded by the RAB11B gene. Rab11b is reported as most abundantly expressed in brain, heart and testes.
Rab9 effector protein with Kelch motifs also known as p40 is a protein that in humans is encoded by the RABEPK gene.
Jennifer Lippincott-Schwartz is a Senior Group Leader at Howard Hughes Medical Institute's Janelia Research Campus and a founding member of the Neuronal Cell Biology Program at Janelia. Previously, she was the Chief of the Section on Organelle Biology in the Cell Biology and Metabolism Program, in the Division of Intramural Research in the Eunice Kennedy Shriver National Institute of Child Health and Human Development at the National Institutes of Health from 1993 to 2016. Lippincott-Schwartz received her PhD from Johns Hopkins University, and performed post-doctoral training with Richard Klausner at the NICHD, NIH in Bethesda, Maryland.
Syntaxin-10 (STX10) is a SNARE protein that is encoded by the STX10 gene. This protein is found in most vertebrates but is noticeably absent from mice. As with other SNARE proteins, STX10 facilitates vesicle fusion and thus is important for intracellular trafficking of proteins and other cellular components. More specifically, STX10 has been implicated in endosome to Golgi trafficking of the mannose 6-phosphate receptor and glucose transporter type 4.
Anne Spang is a German Biochemist/Cell Biologist and Professor at the Biozentrum University of Basel, Switzerland.
Rab GTPases are molecular switches that regulate membrane traffic. They are active in their GTP-bound form and inactive when bound to GDP. The GTPase YPT1, and its mammalian homologue Rab1, regulate membrane-tethering events on three different pathways: autophagy, ER-Golgi, and intra-Golgi traffic. In the yeast Saccharomyces cerevisiae, many of the ATG proteins needed for macroautophagy are shared with the biosynthetic cytoplasm to the vacuole-targeting (CVT) pathway that transports certain hydrolases into the vacuole. Both pathways require YPT1; however, only the macroautophagy pathway is conserved in higher eukaryotes. In the macroautophagy pathway, Rab1 mediates the recruitment of Atg1 to the PAS. Rab1 regulates macroautophagy by recruiting its effector, Atg1, to the PAS to tether Atg9 vesicles to each other or to other membranes.
Sandra Louise Schmid is the first Chief Scientific Officer of the Chan Zuckerberg Biohub. She is a Canadian cell biologist by training; prior to her move to CZ Biohub, she was Professor and Chair of the Cell Biology Department at the University of Texas Southwestern Medical Center. Throughout her academic career, she has authored over 105 publications on the molecular mechanism and regulation of clathrin-mediated endocytosis and the structure and function of the GTPase dynamin and mechanisms governing membrane fission. She was the first to identify dynamin's key role in endocytosis. She is a co-founder of the journal Traffic and has been the Editor-in-Chief of Molecular Biology of the Cell, and the President of the American Society for Cell Biology.
Anne Jacqueline Ridley is professor of Cell Biology and Head of School for Cellular and Molecular Medicine at the University of Bristol. She was previously a professor at King's College London.
Yukiko Goda is a Japanese molecular biologist who is a professor and group leader at the Okinawa Institute of Science and Technology. Her research considers neural communication through synapses. She was elected a Member of the European Molecular Biology Organization in 2023.
Gia Voeltz is an American cell biologist. She is a professor of Molecular, Cellular and Developmental Biology at the University of Colorado Boulder and a Howard Hughes Medical Institute Investigator. She is known for her research identifying the factors and unraveling the mechanisms that determine the structure and dynamics of the largest organelle in the cell: the endoplasmic reticulum. Her lab has produced paradigm shifting studies on organelle membrane contact sites that have revealed that most cytoplasmic organelles are not isolated entities but are instead physically tethered to an interconnected ER membrane network.
Ras-related protein Rab-4B is a protein that in humans is encoded by the RAB4B gene.
