The actin cytoskeleton provides scaffolding and physical force to effect fundamental processes such as motility, cytokinesis and vesicle trafficking. The Arp2/3 complex nucleates actin structures and contributes to endocytic vesicle invagination and trafficking away from the plasma membrane. Internalisation and directed recycling of integrins are major driving forces for invasive cell motility ...

The establishment of cell polarity involves positive-feedback mechanisms that concentrate polarity regulators, including the conserved GTPase Cdc42p, at the "front" of the polarized cell. Previous studies in yeast suggested the presence of two parallel positive-feedback loops, one operating as a diffusion-based system, and the other involving actin-directed trafficking of Cdc42p on vesicles. F-...

The GABA-synthesizing enzyme GAD65 is synthesized as a soluble cytosolic protein but undergoes post-translational modification(s) to become anchored to the cytosolic face of Golgi membranes before targeting to synaptic vesicle membranes in neuroendocrine cells. Palmitoylation of cysteines 30 and 45 in GAD65 is not required for targeting to Golgi membranes but is crucial for post-Golgi trafficki...

Phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) signaling is transient and spatially confined in live cells. How this pattern of signaling regulates transmitter release and hormone secretion has not been addressed. We devised an optogenetic approach to control PI(4,5)P2 levels in time and space in insulin-secreting cells. Combining this approach with total internal reflection fluorescence mic...

Parkinson's disease is associated with multiplication of the α-synuclein gene and abnormal accumulation of the protein. In animal models, α-synuclein overexpression broadly impairs synaptic vesicle trafficking. However, the exact steps of the vesicle trafficking pathway affected by excess α-synuclein and the underlying molecular mechanisms remain unknown. Therefore we acutely increased synuclei...

The native function of α-synuclein is thought to involve regulation of synaptic vesicle trafficking. Recent work has also implicated a role in neurotransmission, possibly through interactions with the proteins involved in synaptic vesicle fusion. Here, we demonstrate that α-synuclein inhibits SNARE-mediated vesicle fusion through binding the membrane, without a direct interaction between α-synu...

High temperature stress is one of the most threatening abiotic stresses for plants limiting crop productivity world-wide. Altered developmental responses to moderate-high has been shown be linked intracellular auxin homeostasis regulated by both biosynthesis and transport. Trafficking carrier proteins plays a major role in maintaining cellular homeostasis. The trafficking largely relies on cyto...

Biological tubes consist of polarized epithelial cells with apical membranes building the central lumen and basolateral membranes contacting adjacent cells or the extracellular matrix. Cellular polarity requires distinct inputs from outside the cell, e.g., the matrix, inside the cell, e.g., vesicular trafficking and the plasma membrane and its junctions.(1) Many highly conserved polarity cues h...

Small GTPase proteins play essential roles in the regulation of vesicular trafficking systems in eukaryotic cells. Two types of small GTPases, secretion-associated Ras-related protein (Sar) and ADP-ribosylation factor (Arf), act in the biogenesis of transport vesicles. Sar/Arf GTPases function as molecular switches by cycling between active, GTP-bound and inactive, GDP-bound forms, catalyzed by...

PURPOSE Reorganization of cytoskeleton and membrane biogenesis are dynamically coordinated during lens fiber cell differentiation and development to produce an organ with precise dimensions and optical properties. Cargo vesicle trafficking is fundamental to cell elongation and has also been implicated in degenerative disease mechanisms. Alzheimer precursor protein (AbetaPP) acts with kinesin, s...