scholarly journals Mutants in trs120 disrupt traffic from the early endosome to the late Golgi

2005 ◽  
Vol 171 (5) ◽  
pp. 823-833 ◽  
Author(s):  
Huaqing Cai ◽  
Yueyi Zhang ◽  
Marc Pypaert ◽  
Lee Walker ◽  
Susan Ferro-Novick
Keyword(s):  
Coat Protein ◽  
Membrane Traffic ◽  
Transport Protein ◽  
Early Endosome ◽  
Specific Gene ◽  
Membrane Structures ◽  
Vesicle Traffic ◽  
Large Complex ◽  
Protein Particle ◽  
Endosomal Pathway

Transport protein particle (TRAPP), a large complex that mediates membrane traffic, is found in two forms (TRAPPI and -II). Both complexes share seven subunits, whereas three subunits (Trs130p, -120p, and -65p) are specific to TRAPPII. Previous studies have shown that mutations in the TRAPPII-specific gene trs130 block traffic through or from the Golgi. Surprisingly, we report that mutations in trs120 do not block general secretion. Instead, trs120 mutants accumulate aberrant membrane structures that resemble Berkeley bodies and disrupt the traffic of proteins that recycle through the early endosome. Mutants defective in recycling also display a defect in the localization of coat protein I (COPI) subunits, implying that Trs120p may participate in a COPI-dependent trafficking step on the early endosomal pathway. Furthermore, we demonstrate that Trs120p largely colocalizes with the late Golgi marker Sec7p. Our findings imply that Trs120p is required for vesicle traffic from the early endosome to the late Golgi.

Membrane traffic related to endosome dynamics and protein secretion in filamentous fungi

2021 ◽  
Author(s):  
Yujiro Higuchi
Keyword(s):  
Filamentous Fungi ◽  
Protein Secretion ◽  
Secretory Pathway ◽  
Molecular Mechanisms ◽  
Membrane Traffic ◽  
Early Endosome ◽  
Protein Glycosylation ◽  
Hyphal Cell ◽  
Cell Factories ◽  
Membrane Contacts

ABSTRACT In eukaryotic cells, membrane-surrounded organelles are orchestrally organized spatiotemporally under environmental situations. Among such organelles, vesicular transports and membrane contacts occur to communicate each other, so-called membrane traffic. Filamentous fungal cells are highly polarized and thus membrane traffic is developed to have versatile functions. Early endosome (EE) is an endocytic organelle that dynamically exhibits constant long-range motility through the hyphal cell, which is proven to have physiological roles, such as other organelle distribution and signal transduction. Since filamentous fungal cells are also considered as cell factories, to produce valuable proteins extracellularly, molecular mechanisms of secretory pathway including protein glycosylation have been well investigated. In this review, molecular and physiological aspects of membrane traffic especially related to EE dynamics and protein secretion in filamentous fungi are summarized, and perspectives for application are also described.

scholarly journals TRAPPopathies: An emerging set of disorders linked to variations in the genes encoding transport protein particle (TRAPP)‐associated proteins

Traffic ◽  
2018 ◽  
Vol 20 (1) ◽  
pp. 5-26 ◽  
Author(s):  
Michael Sacher ◽  
Nassim Shahrzad ◽  
Hiba Kamel ◽  
Miroslav P. Milev
Keyword(s):  
Transport Protein ◽  
Genes Encoding ◽  
Associated Proteins ◽  
Protein Particle

scholarly journals Interactions between Transport Protein Particle (TRAPP) complexes and RabGTPases in Arabidopsis

2019 ◽  
Vol 100 (2) ◽  
pp. 279-297 ◽  
Author(s):  
Monika Kalde ◽  
Liam Elliott ◽  
Raksha Ravikumar ◽  
Katarzyna Rybak ◽  
Melina Altmann ◽  
...  
Keyword(s):  
Transport Protein ◽  
Protein Particle

Biochemical consequences of sedlin mutations that cause spondyloepiphyseal dysplasia tarda

2009 ◽  
Vol 423 (2) ◽  
pp. 233-242 ◽  
Author(s):  
Mei Y. Choi ◽  
Caleb C. Y. Chan ◽  
Danny Chan ◽  
Keith D. K. Luk ◽  
Kathryn S. E. Cheah ◽  
...  
Keyword(s):  
Late Onset ◽  
Transport Protein ◽  
Missense Mutations ◽  
Wild Type ◽  
Spondyloepiphyseal Dysplasia ◽  
Type Protein ◽  
Wild Type Protein ◽  
Protein Particle ◽  
Spondyloepiphyseal Dysplasia Tarda

SEDT (spondyloepiphyseal dysplasia tarda) is a late-onset X-linked recessive skeletal dysplasia caused by mutations in the gene SEDL coding for sedlin. In the present paper, we investigated four missense mutations observed in SEDT and compare biochemical and cellular characteristics relative to the wild-type protein to address the mechanism of disease and to gain insight into the function of the sedlin protein. In situ hybridization and immunohistochemical experiments in mouse growth plates revealed sedlin to be predominantly expressed in proliferating and hypertrophic chondrocytes. Cell culture studies showed that the wild-type protein localized predominantly in the vicinity of the nucleus and the Golgi, with further localization around the cytoplasm, whereas mutation resulted in mislocalization. The D47Y mutant was expressed similarly to the wild-type, but the S73L, F83S and V130D mutants showed particularly low levels of expression that were rescued in the presence of the proteasome inhibitor MG132 (benzyloxycarbonyl-leucylleucylleucinal). Furthermore, whereas the D47Y mutant folded similarly and had similar stability to the wild-type sedlin as shown by CD and fluorescence, the S73L, F83S and V130D mutants all misfolded during expression. Two independent assays showed that the D47Y mutation resulted in an increased affinity for the transport protein particle component Bet3 compared with the wild-type sedlin. Our results suggest that the sedlin mutations S73L, F83S and V130D cause SEDT by sedlin misfolding, whereas the D47Y mutation may influence normal TRAPP (transport protein particle) dynamics.

Vps1, a recycling factor for the traffic from early endosome to the late Golgi

2013 ◽  
Vol 91 (6) ◽  
pp. 455-465 ◽  
Author(s):  
Joshua Lukehart ◽  
Chad Highfill ◽  
Kyoungtae Kim
Keyword(s):  
Cell Survival ◽  
Budding Yeast ◽  
Membrane Traffic ◽  
Early Endosome ◽  
Genetic Interactions ◽  
Cellular Membranes ◽  
Early Endosomes ◽  
Survival And Growth ◽  
Mild Defect ◽  
Actin Cables

Recycling of cellular membranes and their constituents plays a role for cell survival and growth. In the budding yeast, there are recycling traffics from early and late endosomal compartments to the late Golgi. Here, we examined a possible role for Vps1, a large GTPase, in the recycling traffic of GFP-Snc1 from early endosomes to the late Golgi. In the absence of Vps1 we observed an aberrant accumulation of GFP-Snc1 puncta in the cytoplasm that we identified as early endosomes. The N-terminal GTPase and the C-terminal GED domains of Vps1 are essential for Vps1’s function in Snc1 recycling. Our finding of genetic interactions of VPS1 with genes involved in early endosome-to-Golgi traffic further suggests Vps1 functions as a recycling factor in the membrane traffic. Finally, we provide evidence that the severe accumulation of GFP-Snc1 cytoplasmic puncta in vps1Δ cells is attributed to a mild defect in the retention of the GARP component Vps51 at the late Golgi, as well as a severe disruption of actin cables.

scholarly journals Arabidopsis chloroplast lipid transport protein TGD2 disrupts membranes and is part of a large complex

2011 ◽  
Vol 66 (5) ◽  
pp. 759-769 ◽  
Author(s):  
Rebecca Roston ◽  
Jinpeng Gao ◽  
Changcheng Xu ◽  
Christoph Benning
Keyword(s):  
Transport Protein ◽  
Lipid Transport ◽  
Large Complex

scholarly journals Inactivation of Two Dictyostelium discoideum Genes, DdPIK1 and DdPIK2, Encoding Proteins Related to Mammalian Phosphatidylinositide 3-kinases, Results in Defects in Endocytosis, Lysosome to Postlysosome Transport, and Actin Cytoskeleton Organization

1997 ◽  
Vol 136 (6) ◽  
pp. 1271-1286 ◽  
Author(s):  
Greg Buczynski ◽  
Bryon Grove ◽  
Anson Nomura ◽  
Maurice Kleve ◽  
John Bush ◽  
...  
Keyword(s):  
Actin Cytoskeleton ◽  
Dictyostelium Discoideum ◽  
Mutant Strain ◽  
Fluorescent Microscopy ◽  
Membrane Traffic ◽  
Fluid Phase ◽  
Cytoskeleton Organization ◽  
Actin Cytoskeleton Organization ◽  
Endosomal Pathway ◽  
Mutant Cells

Phosphatidylinositide 3-kinases (PI 3-kinases) have been implicated in controlling cell proliferation, actin cytoskeleton organization, and the regulation of vesicle trafficking between intracellular organelles. There are at least three genes in Dictyostelium discoideum, DdPIK1, DdPIK2, and DdPIK3, encoding proteins most closely related to the mammalian 110-kD PI-3 kinase in amino acid sequence within the kinase domain. A mutant disrupted in DdPIK1 and DdPIK2 (Δddpik1/ddpik2) grows slowly in liquid medium. Using FITC-dextran (FD) as a fluid phase marker, we determined that the mutant strain was impaired in pinocytosis but normal in phagocytosis of beads or bacteria. Microscopic and biochemical approaches indicated that the transport rate of fluid-phase from acidic lysosomes to non-acidic postlysosomal vacuoles was reduced in mutant cells resulting in a reduction in efflux of fluid phase. Mutant cells were also almost completely devoid of large postlysosomal vacuoles as determined by transmission EM. However, Δddpik1/ddpik2 cells functioned normally in the regulation of other membrane traffic. For instance, radiolabel pulse-chase experiments indicated that the transport rates along the secretory pathway and the sorting efficiency of the lysosomal enzyme α-mannosidase were normal in the mutant strain. Furthermore, the contractile vacuole network of membranes (probably connected to the endosomal pathway by membrane traffic) was functionally and morphologically normal in mutant cells. Light microscopy revealed that Δddpik1/ddpik2 cells appeared smaller and more irregularly shaped than wild-type cells; 1–3% of the mutant cells were also connected by a thin cytoplasmic bridge. Scanning EM indicated that the mutant cells contained numerous filopodia projecting laterally and vertically from the cell surface, and fluorescent microscopy indicated that these filopodia were enriched in F-actin which accumulated in a cortical pattern in control cells. Finally, Δddpik1/ddpik2 cells responded and moved more rapidly towards cAMP. Together, these results suggest that Dictyostelium DdPIK1 and DdPIK2 gene products regulate multiple steps in the endosomal pathway, and function in the regulation of cell shape and movement perhaps through changes in actin organization.

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