scholarly journals Mechanism of Residence of Cytochrome B(5), a Tail-Anchored Protein, in the Endoplasmic Reticulum

2000 ◽  
Vol 148 (5) ◽  
pp. 899-914 ◽  
Author(s):  
Emanuela Pedrazzini ◽  
Antonello Villa ◽  
Renato Longhi ◽  
Alessandra Bulbarelli ◽  
Nica Borgese
Keyword(s):  
Endoplasmic Reticulum ◽  
Lipid Bilayer ◽  
Cytochrome B ◽  
Golgi Complex ◽  
Intracellular Trafficking ◽  
Secretory Pathway ◽  
Transmembrane Topology ◽  
Glycosylation Sites ◽  
Cytosolic Domain

Endoplasmic reticulum (ER) proteins maintain their residency by static retention, dynamic retrieval, or a combination of the two. Tail-anchored proteins that contain a cytosolic domain associated with the lipid bilayer via a hydrophobic stretch close to the COOH terminus are sorted within the secretory pathway by largely unknown mechanisms. Here, we have investigated the mode of insertion in the bilayer and the intracellular trafficking of cytochrome b(5) (b[5]), taken as a model for ER-resident tail-anchored proteins. We first demonstrated that b(5) can acquire a transmembrane topology posttranslationally, and then used two tagged versions of b(5), N-glyc and O-glyc b(5), containing potential N- and O-glycosylation sites, respectively, at the COOH-terminal lumenal extremity, to discriminate between retention and retrieval mechanisms. Whereas the N-linked oligosaccharide provided no evidence for retrieval from a downstream compartment, a more stringent assay based on carbohydrate acquisition by O-glyc b(5) showed that b(5) gains access to enzymes catalyzing the first steps of O-glycosylation. These results suggest that b(5) slowly recycles between the ER and the cis-Golgi complex and that dynamic retrieval as well as retention are involved in sorting of tail-anchored proteins.

scholarly journals New Mutants of Saccharomyces cerevisiae Affected in the Transport of Proteins From the Endoplasmic Reticulum to the Golgi Complex

Genetics ◽  
1996 ◽  
Vol 142 (2) ◽  
pp. 393-406 ◽  
Author(s):  
Linda J Wuestehube ◽  
Rainer Duden ◽  
Arlene Eun ◽  
Susan Hamamoto ◽  
Paul Korn ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Golgi Complex ◽  
Secretory Pathway ◽  
Secretory Protein ◽  
Temperature Sensitive ◽  
Nonpermissive Temperature ◽  
Membrane Structures ◽  
Α Subunit ◽  
Complementation Groups ◽  
Vacuolar Protein

Abstract We have isolated new temperature-sensitive mutations in five complementation groups, sec31-sec35, that are defective in the transport of proteins from the endoplasmic reticulum (ER) to the Golgi complex. The sec31-sec35 mutants and additional alleles of previously identified sec and vacuolar protein sorting (vps) genes were isolated in a screen based on the detection of α-factor precursor in yeast colonies replicated to and lysed on nitrocellulose filters. Secretory protein precursors accumulated in sec31-sec35 mutants at the nonpermissive temperature were core-glycosylated but lacked outer chain carbohydrate, indicating that transport was blocked after translocation into the ER but before arrival in the Golgi complex. Electron microscopy revealed that the newly identified sec mutants accumulated vesicles and membrane structures reminiscent of secretory pathway organelles. Complementation analysis revealed that sec32-1 is an allele of BOS1, a gene implicated in vesicle targeting to the Golgi complex, and sec33-1 is an allele of RET1, a gene that encodes the α subunit of coatomer.

scholarly journals Pathogenic Effects of Impaired Retrieval between the Endoplasmic Reticulum and Golgi Complex

2019 ◽  
Vol 20 (22) ◽  
pp. 5614 ◽  
Author(s):  
Hiroshi Kokubun ◽  
Hisayo Jin ◽  
Tomohiko Aoe
Keyword(s):  
Endoplasmic Reticulum ◽  
Golgi Complex ◽  
Secretory Pathway ◽  
Protein Transport ◽  
Receptor Activation ◽  
Toxic Substances ◽  
Bidirectional Transport ◽  
The Unfolded Protein Response ◽  
Kdel Receptor ◽  
Kdel Sequence

Cellular activities, such as growth and secretion, are dependent on correct protein folding and intracellular protein transport. Injury, like ischemia, malnutrition, and invasion of toxic substances, affect the folding environment in the endoplasmic reticulum (ER). The ER senses this information, following which cells adapt their response to varied situations through the unfolded protein response. Activation of the KDEL receptor, resulting from the secretion from the ER of chaperones containing the KDEL sequence, plays an important role in this adaptation. The KDEL receptor was initially shown to be necessary for the retention of KDEL sequence-containing proteins in the ER. However, it has become clear that the activated KDEL receptor also regulates bidirectional transport between the ER and the Golgi complex, as well as from the Golgi to the secretory pathway. In addition, it has been suggested that the signal for KDEL receptor activation may also affect several other cellular activities. In this review, we discuss KDEL receptor-mediated bidirectional transport and signaling and describe disease models and human diseases related to KDEL receptor dysfunction.

scholarly journals Requirement for Neo1p in Retrograde Transport from the Golgi Complex to the Endoplasmic Reticulum

2003 ◽  
Vol 14 (12) ◽  
pp. 4971-4983 ◽  
Author(s):  
Zhaolin Hua ◽  
Todd R. Graham
Keyword(s):  
Endoplasmic Reticulum ◽  
Golgi Complex ◽  
Secretory Pathway ◽  
Protein Transport ◽  
Retrograde Transport ◽  
Transport Pathway ◽  
Transport Defect ◽  
Copii Vesicles ◽  
P Type ◽  
Adp Ribosylation Factor

Neo1p from Saccharomyces cerevisiae is an essential P-type ATPase and potential aminophospholipid translocase (flippase) in the Drs2p family. We have previously implicated Drs2p in protein transport steps in the late secretory pathway requiring ADP-ribosylation factor (ARF) and clathrin. Here, we present evidence that epitope-tagged Neo1p localizes to the endoplasmic reticulum (ER) and Golgi complex and is required for a retrograde transport pathway between these organelles. Using conditional alleles of NEO1, we find that loss of Neo1p function causes cargo-specific defects in anterograde protein transport early in the secretory pathway and perturbs glycosylation in the Golgi complex. Rer1-GFP, a protein that cycles between the ER and Golgi complex in COPI and COPII vesicles, is mislocalized to the vacuole in neo1-ts at the nonpermissive temperature. These phenotypes suggest that the anterograde protein transport defect is a secondary consequence of a defect in a COPI-dependent retrograde pathway. We propose that loss of lipid asymmetry in the cis Golgi perturbs retrograde protein transport to the ER.

scholarly journals KDEL and KKXX Retrieval Signals Appended to the Same Reporter Protein Determine Different Trafficking between Endoplasmic Reticulum, Intermediate Compartment, and Golgi Complex

2003 ◽  
Vol 14 (3) ◽  
pp. 889-902 ◽  
Author(s):  
Mariano Stornaiuolo ◽  
Lavinia V. Lotti ◽  
Nica Borgese ◽  
Maria-Rosaria Torrisi ◽  
Giovanna Mottola ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Steady State ◽  
Golgi Complex ◽  
Secretory Pathway ◽  
Molecular Mechanisms ◽  
Reporter Protein ◽  
Transport Vesicles ◽  
Efficient Retrieval ◽  
Intermediate Compartment ◽  
Almost All

Many endoplasmic reticulum (ER) proteins maintain their residence by dynamic retrieval from downstream compartments of the secretory pathway. In previous work we compared the retrieval process mediated by the two signals, KKMP and KDEL, by appending them to the same neutral reporter protein, CD8, and found that the two signals determine a different steady-state localization of the reporter. CD8-K (the KDEL-bearing form) was restricted mainly to the ER, whereas CD8-E19 (the KKMP-bearing form) was distributed also to the intermediate compartment and Golgi complex. To investigate whether this different steady-state distribution reflects a difference in exit rates from the ER and/or in retrieval, we have now followed the first steps of export of the two constructs from the ER and their trafficking between ER and Golgi complex. Contrary to expectation, we find that CD8-K is efficiently recruited into transport vesicles, whereas CD8-E19 is not. Thus, the more restricted ER localization of CD8-K must be explained by a more efficient retrieval to the ER. Moreover, because most of ER resident CD8-K is not O-glycosylated but almost all CD8-E19 is, the results suggest that CD8-K is retrieved from the intermediate compartment, before reaching the Golgi, whereO-glycosylation begins. These results illustrate how different retrieval signals determine different trafficking patterns and pose novel questions on the underlying molecular mechanisms.

scholarly journals Surf4 Promotes Endoplasmic Reticulum Exit of the Lysosomal Prosaposin-Progranulin Complex

2021 ◽  
Author(s):  
S. Devireddy ◽  
S.M. Ferguson
Keyword(s):  
Endoplasmic Reticulum ◽  
Frontotemporal Dementia ◽  
Lysosomal Storage Disease ◽  
Intracellular Trafficking ◽  
Secretory Pathway ◽  
Storage Disease ◽  
Neuronal Ceroid Lipofuscinosis ◽  
Lysosomal Storage ◽  
Efficient Delivery ◽  
Lysosomal Protein

AbstractProgranulin is a lysosomal protein whose haploinsufficiency causes frontotemporal dementia while homozygous loss of progranulin causes neuronal ceroid lipofuscinosis, a lysosomal storage disease. The sensitivity of cells to progranulin deficiency raises important questions about how cells coordinate intracellular trafficking of progranulin to ensure its efficient delivery to lysosomes. In this study, we discover that progranulin interacts with prosaposin, another lysosomal protein, within the lumen of the endoplasmic reticulum (ER) and that prosaposin is required for the efficient ER exit of progranulin. Mechanistically, we identify an interaction between prosaposin and Surf4, a receptor that promotes loading of lumenal cargos into COPII coated vesicles, and establish that Surf4 is critical for the efficient export of progranulin and prosaposin from the ER. Collectively, this work demonstrates a network of interactions occurring early in the secretory pathway that promote the ER exit and subsequent lysosomal delivery of newly translated progranulin and prosaposin.

Efficient progranulin exit from the ER requires its interaction with prosaposin, a Surf4 cargo

2021 ◽  
Vol 221 (2) ◽  
Author(s):  
Swathi Devireddy ◽  
Shawn M. Ferguson
Keyword(s):  
Endoplasmic Reticulum ◽  
Frontotemporal Dementia ◽  
Lysosomal Storage Disease ◽  
Intracellular Trafficking ◽  
Secretory Pathway ◽  
Storage Disease ◽  
Neuronal Ceroid Lipofuscinosis ◽  
Lysosomal Storage ◽  
Efficient Delivery ◽  
Lysosomal Protein

Progranulin is a lysosomal protein whose haploinsufficiency causes frontotemporal dementia, while homozygous loss of progranulin causes neuronal ceroid lipofuscinosis, a lysosomal storage disease. The sensitivity of cells to progranulin deficiency raises important questions about how cells coordinate intracellular trafficking of progranulin to ensure its efficient delivery to lysosomes. In this study, we discover that progranulin interactions with prosaposin, another lysosomal protein, first occur within the lumen of the endoplasmic reticulum (ER) and are required for the efficient ER exit of progranulin. Mechanistically, we identify an interaction between prosaposin and Surf4, a receptor that promotes loading of lumenal cargos into COPII-coated vesicles, and establish that Surf4 is critical for the efficient export of progranulin and prosaposin from the ER. Collectively, this work demonstrates that a network of interactions occurring early in the secretory pathway promote the ER exit and subsequent lysosomal delivery of newly translated progranulin and prosaposin.

Potassium depletion inhibits the intracellular transport of secretory proteins between the endoplasmic reticulum and the Golgi complex

1989 ◽  
Vol 92 (2) ◽  
pp. 173-185
Author(s):  
J.D. Judah ◽  
K.E. Howell ◽  
J.A. Taylor ◽  
P.S. Quinn
Keyword(s):  
Endoplasmic Reticulum ◽  
Golgi Complex ◽  
Intracellular Transport ◽  
Secretory Pathway ◽  
Subcellular Fractionation ◽  
Secretory Proteins ◽  
Mature Form ◽  
Processing Enzymes ◽  
Microscopic Studies ◽  
K Depletion

In this paper we show that hepatocytes that have been depleted of K+ secrete albumin, alpha-1-anti-trypsin and transferrin at a slower rate than cells to which K+ has been returned. K+ depletion has no effect on the intracellular nucleotide pools, and we provide evidence that the inhibitions of secretion caused by depletion of K+ and depletion of ATP are independent. Studies of the processing of alpha-1-anti-trypsin show that K+ depletion inhibits the formation of the mature form of the protein, but that immature forms are never secreted. In cells to which K+ was returned, secretion of the mature form was restored. This implies that transport is blocked at a point before the proteins reach the processing enzymes. Proteins delayed by K+ depletion are not removed from the secretory pathway, but are free to mix with protein synthesized subsequently. These data are supported by subcellular fractionation experiments, which show that the secretory proteins are delayed before reaching the Golgi complex, and by immunoelectron microscopic studies. These show that in K+-deficient cells the morphology of both the endoplasmic reticulum and the Golgi complex is normal. The secretory proteins are trapped in smooth vesicles that contain reaction product when incubated for glucose-6-phosphatase, a marker for the endoplasmic reticulum.

scholarly journals Early Stages of the Secretory Pathway, but Not Endosomes, Are Required for Cvt Vesicle and Autophagosome Assembly in Saccharomyces cerevisiae

2004 ◽  
Vol 15 (5) ◽  
pp. 2189-2204 ◽  
Author(s):  
Fulvio Reggiori ◽  
Chao-Wen Wang ◽  
Usha Nair ◽  
Takahiro Shintani ◽  
Hagai Abeliovich ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Golgi Complex ◽  
Secretory Pathway ◽  
Membrane Vesicle ◽  
Endomembrane System ◽  
Vesicle Membrane ◽  
Double Membrane ◽  
Vesicle Biogenesis ◽  
Molecular Components ◽  
Vacuolar Trafficking

The Cvt pathway is a biosynthetic transport route for a distinct subset of resident yeast vacuolar hydrolases, whereas macroautophagy is a nonspecific degradative mechanism that allows cell survival during starvation. Yet, these two vacuolar trafficking pathways share a number of identical molecular components and are morphologically very similar. For example, one of the hallmarks of both pathways is the formation of double-membrane cytosolic vesicles that sequester cargo before vacuolar delivery. The origin of the vesicle membrane has been controversial and various lines of evidence have implicated essentially all compartments of the endomembrane system. Despite the analogies between the Cvt pathway and autophagy, earlier work has suggested that the origin of the engulfing vesicle membranes is different; the endoplasmic reticulum is proposed to be required only for autophagy. In contrast, in this study we demonstrate that the endoplasmic reticulum and/or Golgi complex, but not endosomal compartments, play an important role for both yeast transport routes. Along these lines, we demonstrate that Berkeley bodies, a structure generated from the Golgi complex in sec7 cells, are immunolabeled with Atg8, a structural component of autophagosomes. Finally, we also show that none of the yeast t-SNAREs are located at the preautophagosomal structure, the presumed site of double-membrane vesicle formation. Based on our results, we propose two models for Cvt vesicle biogenesis.

scholarly journals Assembly of influenza hemagglutinin trimers and its role in intracellular transport.

1986 ◽  
Vol 103 (4) ◽  
pp. 1179-1191 ◽  
Author(s):  
C S Copeland ◽  
R W Doms ◽  
E M Bolzau ◽  
R G Webster ◽  
A Helenius
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Golgi Complex ◽  
Intracellular Transport ◽  
Secretory Pathway ◽  
Quaternary Structure ◽  
Subunit Interactions ◽  
Oligomer Formation ◽  
Influenza Hemagglutinin ◽  
Triton X

The hemagglutinin (HA) of influenza virus is a homotrimeric integral membrane glycoprotein. It is cotranslationally inserted into the endoplasmic reticulum as a precursor called HA0 and transported to the cell surface via the Golgi complex. We have, in this study, investigated the kinetics and cellular location of the assembly reaction that results in HA0 trimerization. Three independent criteria were used for determining the formation of quaternary structure: the appearance of an epitope recognized by trimer-specific monoclonal antibodies; the acquisition of trypsin resistance, a characteristic of trimers; and the formation of stable complexes which cosedimented with the mature HA0 trimer (9S20,w) in sucrose gradients containing Triton X-100. The results showed that oligomer formation is a posttranslational event, occurring with a half time of approximately 7.5 min after completion of synthesis. Assembly occurs in the endoplasmic reticulum, followed almost immediately by transport to the Golgi complex. A stabilization event in trimer structure occurs when HA0 leaves the Golgi complex or reaches the plasma membrane. Approximately 10% of the newly synthesized HA0 formed aberrant trimers which were not transported from the endoplasmic reticulum to the Golgi complex or the plasma membrane. Taken together the results suggested that formation of correctly folded quaternary structure constitutes a key event regulating the transport of the protein out of the endoplasmic reticulum. Further changes in subunit interactions occur as the trimers move along the secretory pathway.

scholarly journals Yos1p Is a Novel Subunit of the Yip1p–Yif1p Complex and Is Required for Transport between the Endoplasmic Reticulum and the Golgi Complex

2005 ◽  
Vol 16 (4) ◽  
pp. 1673-1683 ◽  
Author(s):  
Matthew Heidtman ◽  
Catherine Z. Chen ◽  
Ruth N. Collins ◽  
Charles Barlowe
Keyword(s):  
Endoplasmic Reticulum ◽  
Golgi Complex ◽  
Secretory Pathway ◽  
Integral Membrane Protein ◽  
Rab Gtpases ◽  
Reading Frame ◽  
Multicopy Suppressor ◽  
Transport Vesicles ◽  
Identification And Characterization

Yeast Yip1p is a member of a conserved family of transmembrane proteins that interact with Rab GTPases. Previous studies also have indicated a role for Yip1p in the biogenesis of endoplasmic reticulum (ER)-derived COPII transport vesicles. In this report, we describe the identification and characterization of the uncharacterized open reading frame YER074W-A as a novel multicopy suppressor of the thermosensitive yip1-4 strain. We have termed this gene Yip One Suppressor 1 (YOS1). Yos1p is essential for growth and for function of the secretory pathway; depletion or inactivation of Yos1p blocks transport between the ER and the Golgi complex. YOS1 encodes an integral membrane protein of 87 amino acids that is conserved in eukaryotes. Yos1p localizes to ER and Golgi membranes and is efficiently packaged into ER-derived COPII transport vesicles. Yos1p associates with Yip1p and Yif1p, indicating Yos1p is a novel subunit of the Yip1p–Yif1p complex.

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