A5013730838- Cellular transport and secretion
- Endoplasmic Reticulum Stress and Disease
- Lipid Membrane Structure and Behavior
- Microtubule and mitosis dynamics
- Pancreatic function and diabetes
- Glycosylation and Glycoproteins Research
- Retinal Development and Disorders
- Photoreceptor and optogenetics research
- Photosynthetic Processes and Mechanisms
- Calcium signaling and nucleotide metabolism
- RNA Interference and Gene Delivery
- Erythrocyte Function and Pathophysiology
- Escherichia coli research studies
- Advanced Fluorescence Microscopy Techniques
- Viral gastroenteritis research and epidemiology
- Galectins and Cancer Biology
- Image Processing Techniques and Applications
- Monoclonal and Polyclonal Antibodies Research
- Ion channel regulation and function
- Mitochondrial Function and Pathology
- Virus-based gene therapy research
- Trace Elements in Health
- Proteoglycans and glycosaminoglycans research
- Cell Image Analysis Techniques
- Peptidase Inhibition and Analysis
Carnegie Mellon University
2012-2022
Yale University
2017
University of Pittsburgh
2013
Institució Catalana de Recerca i Estudis Avançats
2009
Max Planck Institute of Molecular Cell Biology and Genetics
2004
University of Basel
1993-1995
University of California, San Francisco
1986-1991
Friedrich Schiller University Jena
1991
Oregon National Primate Research Center
1986
Reed College
1986
The Golgi complex consists of a series stacked cisternae in most eukaryotes. Morphological studies indicate the existence intercisternal cross-bridge structures that may mediate stacking, but their identity is unknown. We have identified 400-kDa protein, giantin, localized to because its staining double immunofluorescence experiments was coincident with galactosyltransferase, both untreated cells and treated agents disrupt structure. A monoclonal antibody against giantin yielded one avian...
Peri-centrosomal positioning of the mammalian Golgi apparatus is known to involve microtubule-based motility, but its importance for cellular physiology a major unanswered question. Here, we identify golgin-160 and GMAP210 as proteins required centripetal motility membranes. In absence either golgin, peri-centrosomal was disrupted while cytoskeleton remained intact. Although secretion persisted with normal kinetics, it evenly distributed in response wounding rather than directed wound edge....
The presence of unique proteins in synaptic vesicles neurons suggests selective targeting during vesicle formation. Endocrine, but not other cells, also express membrane and target them selectively to small intracellular vesicles. We show that the rat pheochromocytoma cell line, PC12, has a population with sedimentation density properties very similar those brain When synaptophysin is expressed nonneuronal it found organelles are size major protein isolated from PC12 cells be synaptophysin,...
Recent work indicates that mitogen-activated protein kinase (MEK)1 signaling at the G2/M cell cycle transition unlinks contiguous mammalian Golgi apparatus and this regulates progression. Here, we sought to determine role in pathway of reassembly (GRASP)55, a Golgi-localized target MEK/extracellular signal-regulated (ERK) phosphorylation mitosis. In support hypothesis GRASP55 is inhibited late G2 phase, causing unlinking ribbon, found HeLa cells depleted show fragmented similar control...
Shunning Shiga Infection with bacteria harboring toxin is responsible for more than 1 million deaths annually worldwide. Antidotes the are not available, and treatment antibiotics contraindicated because it increases risk of release (from dead bacteria) leads to severe forms disease. Manganese an essential nutrient its toxicology in humans well studied; inhibits normal trafficking tissue culture cells. Mukhopadhyay Linstedt (p. 332 ) found that levels Mn 2+ caused no deleterious effects...
Serum GP73 levels are significantly increased in patients with hepatocellular carcinoma (HCC), potentially providing a marker for early detection. However, is an integral membrane protein localized to the cis Golgi and not known be secreted. Based on its presence sera, we sought determine whether might normally released from cells elucidate mechanism of this release. Indeed, soluble form was cultured compared Golgi-localized full-length protein, molecular weight slightly reduced, suggesting...
Membrane motility is a fundamental characteristic of all eukaryotic cells. One the best-known examples that mammalian Golgi apparatus, where constant inward movement membranes results in its position near centrosome. While it clear minus-end-directed motor dynein required for this process, mechanism and regulation recruitment to remains unknown. Here, we show protein golgin160 recruits membranes. This confers centripetal regulated by GTPase Arf1. Further, during cell division, association...
The role of the mitogen-activated protein kinase (MKK)/extracellular-activated (ERK) pathway in mitotic Golgi disassembly is controversial, part because Golgi-localized targets have not been identified. We observed that reassembly stacking 55 (GRASP55) was phosphorylated cells and extracts, generating a mitosis-specific phospho-epitope recognized by MPM2 mAb. This phosphorylation prevented mutation ERK consensus sites GRASP55. GRASP55 significantly reduced, both vitro vivo, treatment with...
The cis‐Golgi protein GPP130 reversibly redistributes to endosomes upon pH disruption, but the identity of and involved cycling route are unknown. It is also unknown whether any other early Golgi proteins participate in this pathway. Here, we analyze structurally related GP73. Unlike TGN marker TGN38/46, GP73 colocalized redistributed ER after brefeldin A treatment. Nevertheless, disruption by monensin, containing not endosomal markers. In common with redistribution transient appearance on...
It is thought that residents of the Golgi stack are localized by a retention mechanism prevents their forward progress. Nevertheless, some early proteins acquire late modifications. Herein, we describe GPP130 (Golgi phosphoprotein 130 kDa), 130-kDa phosphorylated and glycosylated integral membrane protein to cis/medial Golgi. appears be human counterpart rat protein, cis (GIMPc), previously identified antigen acquires carbohydrate The sequence cDNAs encoding indicate it type II with...
Inhibition of the putative coatomer protein I (COPI) vesicle tethering complex, giantin–p115–GM130, may contribute to mitotic Golgi breakdown. However, neither this, nor role giantin–p115–GM130 complex in maintenance structure has been demonstrated vivo. Therefore, we generated antibodies directed against mapped binding sites each and injected these into mammalian tissue culture cells. Surprisingly, anti-p115 antigiantin caused proteasome-mediated degradation corresponding antigens....
Unlike conventional membrane proteins of the secretory pathway, anchored to cytoplasmic surface membranes by hydrophobic sequences near their C termini follow a posttranslational, signal recognition particle-independent insertion pathway. Many such C-terminally-anchored have restricted intracellular locations, but it is not known whether these are targeted directly in which they will ultimately reside. Here we analyzed sorting Golgi protein giantin, consists rod-shaped 376-kDa domain...
Functional characterization of protein interactions in mammalian systems has been hindered by the inability to perform complementation analyses vivo. Here, we use functional replacement vesicle docking p115 separate its essential from nonessential interactions. is required for biogenesis Golgi apparatus, but it unclear whether mechanism action requires golgin and/or SNARE Short interfering RNA-mediated knockdown induced extensive fragmentation and impaired secretory traffic. Reassembly a...
Two controversies have emerged regarding the signaling pathways that regulate Golgi disassembly at G(2)/M cell cycle transition. The first controversy concerns role of mitogen-activated protein kinase activator (MEK)1, and second participation structure in a novel "checkpoint." A potential simultaneous resolution is suggested by hypothesis MEK1 triggers unlinking late G(2) to control kinetics. Here, we show inhibition RNA interference or using MEK1/2-specific inhibitor U0126 delayed passage...
P-type ATPases transport a wide array of ions, regulate diverse cellular processes, and are implicated in number human diseases. However, mechanisms that increase ion by these ubiquitous proteins not known. SPCA1 is pump transports Mn 2+ from the cytosol into Golgi. We developed an intra-Golgi sensor used it to screen for mutations introduced SPCA1, on basis its predicted structure, which could pumping activity. Remarkably, point mutation (Q747A) size permeation cavity enhanced response...
Formation of the ribbon-like membrane network Golgi apparatus depends on GM130 and GRASP65, but mechanism is unknown. We developed an in vivo organelle tethering assaying which GRASP65 was targeted to mitochondrial outer either directly or via binding GM130. Mitochondria bearing became tethered one another, this depended a PDZ domain that also required for self-interaction. Point mutation within predicted groove blocked both and, gene replacement assay, ribbon formation. Tethering proximate...
Biogenesis of the ribbon-like membrane network mammalian Golgi requires tethering by conserved GRASP domain in GRASP65 and GRASP55, yet mechanism is not fully understood. Here, we report crystal structure GRASP55 domain, which revealed an unusual arrangement two tandem PDZ folds that more closely resemble prokaryotic domains. Biochemical functional data indicated interaction between ligand-binding pocket PDZ1 internal ligand on PDZ2 mediates self-interaction, structural analyses suggest this...
Homotypic membrane tethering by the Golgi reassembly and stacking proteins (GRASPs) is required for lateral linkage of mammalian ministacks into a ribbon-like network. Although GRASP65 GRASP55 are specifically localized to cis medial/trans cisternae, respectively, it unknown whether each GRASP mediates cisternae-specific such specificity necessary compartmentalization. Here was tagged with KillerRed (KR), expressed in HeLa cells, inhibited 1-min exposure light. Significantly, inactivation...