scholarly journals Translocon-associated protein TRAP δ and a novel TRAP-like protein are coordinately expressed with pro-opiomelanocortin in Xenopus intermediate pituitary

1995 ◽  
Vol 312 (1) ◽  
pp. 205-213 ◽  
Author(s):  
J C M Holthuis ◽  
M C H M van Riel ◽  
G J M Martens
Keyword(s):  
Protein Complex ◽  
Transmembrane Protein ◽  
Structural Similarity ◽  
White Background ◽  
Secretory Proteins ◽  
Animal Kingdom ◽  
Alternatively Spliced ◽  
A Subunit ◽  
Polypeptide Chains ◽  
Related Proteins

In the intermediate pituitary gland of Xenopus laevis, the expression levels of the prohormone pro-opiomelanocortin (POMC) can be readily manipulated. When the animal is placed on a black background, the gene for POMC is actively transcribed, whereas on a white background the gene is virtually inactive. In this study, we characterized two genes whose transcript levels in the intermediate pituitary are regulated in coordination with that for POMC. One of these codes for a protein homologous to translocon-associated protein TRAP delta, a subunit of a transmembrane protein complex located at the site where nascent secretory proteins enter the endoplasmic reticulum (ER). Both Xenopus and mice were found to express an alternatively spliced transcript that gives rise to a previously unknown version of the TRAP delta protein. The product of the second gene is a novel and highly conserved protein with structural similarity to glycoprotein gp25L, a constituent of another translocon-associated protein complex. A database search revealed the existence of a novel family of gp25L-related proteins whose members occur throughout the animal kingdom. Together, our data imply that (i) the group of ER proteins surrounding translocating polypeptide chains may be far more complex than previously expected, and (ii) a number of the accessory components of the translocon participate in early steps of prohormone biosynthesis.

scholarly journals Dorsal, a Drosophila Rel-like protein, is phosphorylated upon activation of the transmembrane protein Toll.

1994 ◽  
Vol 14 (6) ◽  
pp. 3559-3568 ◽  
Author(s):  
S K Gillespie ◽  
S A Wasserman
Keyword(s):  
Nuclear Import ◽  
Intracellular Signaling ◽  
Kinase Activity ◽  
Transmembrane Protein ◽  
Immunoblot Analysis ◽  
Phosphorylation State ◽  
Intracellular Signaling Pathway ◽  
Time Period ◽  
Intracellular Proteins ◽  
Related Proteins

The nuclear import of dorsal, a Drosophila Rel homolog, is directed by a spatially restricted extracellular ligand in blastoderm embryos. We have demonstrated both that dorsal is an embryonic phosphoprotein and that its phosphorylation state is regulated by an intracellular signaling pathway initiated by the transmembrane receptor Toll. Immunoblot analysis of cytoplasm from precisely staged embryos revealed that the phosphorylation state of dorsal is altered during the time period that Toll is activated. Moreover, mutations that constitutively activate Toll stimulated dorsal phosphorylation, while mutations that block Toll activation reduced the level of dorsal phosphorylation. We further demonstrated that signal-dependent dorsal phosphorylation is modulated by three intracellular proteins, pelle, tube, and cactus. Using double-mutant embryos, we then explored the nature of the kinase activity responsible for dorsal phosphorylation. We found that free dorsal is a substrate for a signal-independent kinase activity. In addition, our results imply that dorsal is a substrate for a Toll-dependent kinase. These results are consistent with the hypothesis that phosphorylation of Rel-related proteins may be required for the proper nuclear localization and transcriptional activity of these proteins.

scholarly journals Archaeal and Bacterial SecD and SecF Homologs Exhibit Striking Structural and Functional Conservation

2006 ◽  
Vol 188 (4) ◽  
pp. 1251-1259 ◽  
Author(s):  
Nicholas J. Hand ◽  
Reinhard Klein ◽  
Anke Laskewitz ◽  
Mechthild Pohlschröder
Keyword(s):  
Protein Translocation ◽  
Specific Protein ◽  
Cold Sensitivity ◽  
Secretory Proteins ◽  
E Coli ◽  
Functional Conservation ◽  
Membrane Complex ◽  
Hydrophobic Membranes ◽  
A Subunit ◽  
Native Host

ABSTRACT The majority of secretory proteins are translocated into and across hydrophobic membranes via the universally conserved Sec pore. Accessory proteins, including the SecDF-YajC Escherichia coli membrane complex, are required for efficient protein secretion. E. coli SecDF-YajC has been proposed to be involved in the membrane cycling of SecA, the cytoplasmic bacterial translocation ATPase, and in the stabilizing of SecG, a subunit of the Sec pore. While there are no identified archaeal homologs of either SecA or SecG, many archaea possess homologs of SecD and SecF. Here, we present the first study that addresses the function of archaeal SecD and SecF homologs. We show that the SecD and SecF components in the model archaeon Haloferax volcanii form a cytoplasmic membrane complex in the native host. Furthermore, as in E. coli, an H. volcanii ΔsecFD mutant strain exhibits both severe cold sensitivity and a Sec-specific protein translocation defect. Taken together, these results demonstrate significant functional conservation among the prokaryotic SecD and SecF homologs despite the distinct composition of their translocation machineries.

scholarly journals The TP53INP2 Protein Is Required for Autophagy in Mammalian Cells

2009 ◽  
Vol 20 (3) ◽  
pp. 870-881 ◽  
Author(s):  
Jonathan Nowak ◽  
Cendrine Archange ◽  
Joël Tardivel-Lacombe ◽  
Pierre Pontarotti ◽  
Marie-Josèphe Pébusque ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Homo Sapiens ◽  
Transmembrane Protein ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Gene Encoding ◽  
Related Proteins ◽  
Interfering Rna ◽  
Bioinformatic Approach ◽  
Hybrid Screening

Using a bioinformatic approach, we identified a TP53INP1-related gene encoding a protein with 30% identity with tumor protein 53-induced nuclear protein 1 (TP53INP1), which was named TP53INP2. TP53INP1 and TP53INP2 sequences were found in several species ranging from Homo sapiens to Drosophila melanogaster, but orthologues were found neither in earlier eukaryotes nor in prokaryotes. To gain insight into the function of the TP53INP2 protein, we carried out a yeast two-hybrid screening that showed that TP53INP2 binds to the LC3-related proteins GABARAP and GABARAP-like2, and then we demonstrated by coimmunoprecipitation that TP53INP2 interacts with these proteins, as well as with LC3 and with the autophagosome transmembrane protein VMP1. TP53INP2 translocates from the nucleus to the autophagosome structures after activation of autophagy by rapamycin or starvation. Also, we showed that TP53INP2 expression is necessary for autophagosome development because its small interfering RNA-mediated knockdown strongly decreases sensitivity of mammalian cells to autophagy. Finally, we found that interactions between TP53INP2 and LC3 or the LC3-related proteins GABARAP and GABARAP-like2 require autophagy and are modulated by wortmannin as judged by bioluminescence resonance energy transfer assays. We suggest that TP53INP2 is a scaffold protein that recruits LC3 and/or LC3-related proteins to the autophagosome membrane by interacting with the transmembrane protein VMP1. It is concluded that TP53INP2 is a novel gene involved in the autophagy of mammalian cells.

scholarly journals An ankyrin-related gene (unc-44) is necessary for proper axonal guidance in Caenorhabditis elegans.

1995 ◽  
Vol 129 (4) ◽  
pp. 1081-1092 ◽  
Author(s):  
A J Otsuka ◽  
R Franco ◽  
B Yang ◽  
K H Shim ◽  
L Z Tang ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Nucleotide Sequence ◽  
Axon Guidance ◽  
Axonal Guidance ◽  
Related Gene ◽  
Sequence Analyses ◽  
Molecular Analyses ◽  
Molecular Studies ◽  
Alternatively Spliced ◽  
Related Proteins

Caenorhabditis elegans unc-44 mutations result in aberrant axon guidance and fasciculation with inappropriate partners. The unc-44 gene was cloned by transposon tagging, and verified by genetic and molecular analyses of six transposon-induced alleles and their revertants. Nucleotide sequence analyses demonstrated that unc-44 encodes a series of putative ankyrin-related proteins, including AO49 ankyrin (1815 aa, 198.8 kD), AO66 ankyrin (1867 aa, 204 kD), and AO13 ankyrin (< or = 4700 aa, < or = 517 kD). In addition to the major set of approximately 6 kb alternatively spliced transcripts, minor transcripts were observed at approximately 3, 5, 7, and 14 kb. Evidence is provided that mutations in the approximately 14-kb AO13 ankyrin transcript are responsible for the neuronal defects. These molecular studies provide the first evidence that ankyrin-related molecules are required for axonal guidance.

scholarly journals Photovoltage generation in enzymatic bio-hybrid architectures

MRS Advances ◽  
2020 ◽  
Vol 5 (18-19) ◽  
pp. 985-990 ◽  
Author(s):  
Michele Di Lauro ◽  
Gabriella Buscemi ◽  
Michele Bianchi ◽  
Anna De Salvo ◽  
Marcello Berto ◽  
...  
Keyword(s):  
Quantum Yield ◽  
Reaction Center ◽  
Rhodobacter Sphaeroides ◽  
Surface Functionalization ◽  
Protein Complex ◽  
Transmembrane Protein ◽  
Photochemical Activity ◽  
Organic Transistors ◽  
Hybrid Architectures ◽  
Infra Red

AbstractMost of the photochemical activity of bacterial photosynthetic apparatuses occurs in the reaction center, a transmembrane protein complex which converts photons into charge-separated states across the membrane with a quantum yield close to unity, fuelling the metabolism of the organism. Integrating the reaction center from the bacterium Rhodobacter sphaeroides onto electroactive surfaces, it is possible to technologically exploit the efficiency of this natural machinery to generate a photovoltage upon Near Infra-Red illumination, which can be used in electronic architectures working in the electrolytic environment such as electrolyte-gated organic transistors and bio-photonic power cells. Here, photovoltage generation in reaction center-based bio-hybrid architectures is investigated by means of chronopotentiometry, isolating the contribution of the functionalisation layers and defining novel surface functionalization strategies for photovoltage tuning.

scholarly journals Function and Genetics of Dystrophin and Dystrophin-Related Proteins in Muscle

2002 ◽  
Vol 82 (2) ◽  
pp. 291-329 ◽  
Author(s):  
Derek J. Blake ◽  
Andrew Weir ◽  
Sarah E. Newey ◽  
Kay E. Davies
Keyword(s):  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Protein Complex ◽  
Muscle Disease ◽  
Calcium Handling ◽  
Dystrophic Muscle ◽  
Gene Encoding ◽  
Muscle Wasting Disease ◽  
Novel Therapeutic Strategies ◽  
Related Proteins

The X-linked muscle-wasting disease Duchenne muscular dystrophy is caused by mutations in the gene encoding dystrophin. There is currently no effective treatment for the disease; however, the complex molecular pathology of this disorder is now being unravelled. Dystrophin is located at the muscle sarcolemma in a membrane-spanning protein complex that connects the cytoskeleton to the basal lamina. Mutations in many components of the dystrophin protein complex cause other forms of autosomally inherited muscular dystrophy, indicating the importance of this complex in normal muscle function. Although the precise function of dystrophin is unknown, the lack of protein causes membrane destabilization and the activation of multiple pathophysiological processes, many of which converge on alterations in intracellular calcium handling. Dystrophin is also the prototype of a family of dystrophin-related proteins, many of which are found in muscle. This family includes utrophin and α-dystrobrevin, which are involved in the maintenance of the neuromuscular junction architecture and in muscle homeostasis. New insights into the pathophysiology of dystrophic muscle, the identification of compensating proteins, and the discovery of new binding partners are paving the way for novel therapeutic strategies to treat this fatal muscle disease. This review discusses the role of the dystrophin complex and protein family in muscle and describes the physiological processes that are affected in Duchenne muscular dystrophy.

Effects of Resistance Training on the Transmembrane Protein Complex in Young and Older Adults

2006 ◽  
Vol 38 (Supplement) ◽  
pp. S549
Author(s):  
David J. Kosek ◽  
John K. Petrella ◽  
Jeong-Su Kim ◽  
David L. Mayhew ◽  
James M. Cross ◽  
...  
Keyword(s):  
Older Adults ◽  
Resistance Training ◽  
Protein Complex ◽  
Transmembrane Protein

Dissection of functional domains in Bcl-2α by site-directed mutagenesis

1994 ◽  
Vol 72 (11-12) ◽  
pp. 463-469 ◽  
Author(s):  
Christoph Borner ◽  
Reynald Olivier ◽  
Isabelle Martinou ◽  
Chantal Mattmann ◽  
Jurg Tschopp ◽  
...  
Keyword(s):  
Cell Survival ◽  
Protein Structures ◽  
Cell Types ◽  
Site Directed Mutagenesis ◽  
Functional Domains ◽  
Directed Mutagenesis ◽  
Membrane Attachment ◽  
Alternatively Spliced ◽  
Membrane Bound ◽  
Related Proteins

Bcl-2α is a mitochondrial or perinuclear-associated oncoprotein that prolongs the life span of a variety of cell types by interfering with programmed cell death. How Bcl-2 confers cell survival is unknown, although antioxidant and antiprotease functions have been proposed. In addition, protein structures of Bcl-2 that are crucial for its survival activity are still ill-defined. Bcl-2 can occur as Bcl-2α or Bcl-2β, two alternatively spliced forms which solely differ in their carboxyl termini. The finding that Bcl-2α is active and membrane bound, but Bcl-2β is inactive and cytosolic, indicates that the carboxyl terminus contributes to the survival activity of Bcl-2. This region contains two subdomains, a domain X with unknown function and a hydrophobic stretch reported to mediate membrane assocation of Bcl-2α. Recently Bcl-2-related proteins have been identified. These include Bax that heterodimerizes with Bcl-2 and, when overxpressed, counteracts Bcl-2. Bax contains two highly conserved regions of sequence homology with Bcl-2, referred to as Bcl-2 homology 1 and 2 (BH1 and BH2) domains. Site-directed mutagenesis studies have revealed that both domains are not only novel dimerization motifs for the interaction of Bax with Bcl-2 but also crucial for the survival activity of Bcl-2. Interestingly, the C-terminal end of BH2 encompasses the Bcl-2α/β splice site, as well as part of domain X in Bcl-2α. To better define the role of domain X and the hydrophobic C-terminal stretch of Bcl-2α for its survival activity, we created various deletion and truncation mutations in these regions by site-directed mutagenesis. We show here that membrane attachment and therefore the hydrophobic stretch is not required for the survival activity of Bcl-2, but part of domain X appears to be indispensable.Key words: apoptosis, Bcl-2, mutagenesis, cell survival, functional domains.

scholarly journals Tales of the ER-Golgi Frontier: Drosophila-Centric Considerations on Tango1 Function

2021 ◽  
Vol 8 ◽  
Author(s):  
Zhi Feng ◽  
Ke Yang ◽  
José C. Pastor-Pareja
Keyword(s):  
Secretory Pathway ◽  
Transmembrane Protein ◽  
Vesicular Transport ◽  
Fruit Fly ◽  
Evolutionary Perspective ◽  
Animal Evolution ◽  
Golgi Transport ◽  
Er Exit Sites ◽  
Related Proteins

In the secretory pathway, the transfer of cargo from the ER to the Golgi involves dozens of proteins that localize at specific regions of the ER called ER exit sites (ERES), where cargos are concentrated preceding vesicular transport to the Golgi. Despite many years of research, we are missing crucial details of how this highly dynamic ER-Golgi interface is defined, maintained and functions. Mechanisms allowing secretion of large cargos such as the very abundant collagens are also poorly understood. In this context, Tango1, discovered in the fruit fly Drosophila and widely conserved in animal evolution, has received a lot of attention in recent years. Tango1, an ERES-localized transmembrane protein, is the single fly member of the MIA/cTAGE family, consisting in humans of TANGO1 and at least 14 different related proteins. After its discovery in flies, a specific role of human TANGO1 in mediating secretion of collagens was reported. However, multiple studies in Drosophila have demonstrated that Tango1 is required for secretion of all cargos. At all ERES, through self-interaction and interactions with other proteins, Tango1 aids ERES maintenance and tethering of post-ER membranes. In this review, we discuss discoveries on Drosophila Tango1 and put them in relation with research on human MIA/cTAGE proteins. In doing so, we aim to offer an integrated view of Tango1 function and the nature of ER-Golgi transport from an evolutionary perspective.

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