A Caenorhabditis elegans type I TGF beta receptor can function in the absence of type II kinase to promote larval development

Development ◽  
2000 ◽  
Vol 127 (15) ◽  
pp. 3337-3347 ◽  
Author(s):  
C.V. Gunther ◽  
L.L. Georgi ◽  
D.L. Riddle
Keyword(s):  
Caenorhabditis Elegans ◽  
Fluorescent Protein ◽  
Type I ◽  
Receptor Complex ◽  
Type Ii ◽  
Precise Control ◽  
Dauer Larva ◽  
Protein Receptor ◽  
Morphogenetic Protein ◽  
Green Fluorescent

The daf-4 gene encodes a type II bone morphogenetic protein receptor in Caenorhabditis elegans that regulates dauer larva formation, body size and male tail patterning. The putative type I receptor partner for DAF-4 in regulating dauer larva formation is DAF-1. Genetic tests of the mechanism of activation of these receptors show that DAF-1 can signal in the absence of DAF-4 kinase activity. A daf-1 mutation enhances dauer formation in a daf-4 null background, whereas overexpression of daf-1 partially rescues a daf-4 mutant. DAF-1 alone cannot fully compensate for the loss of DAF-4 activity, indicating that nondauer development normally results from the activities of both receptors. DAF-1 signaling in the absence of a type II kinase is unique in the type I receptor family. The activity may be an evolutionary remnant, owing to daf-1's origin near the type I/type II divergence, or it may be an innovation that evolved in nematodes. daf-1 and daf-4 promoters both mediated expression of green fluorescent protein in the nervous system, indicating that a DAF-1/DAF-4 receptor complex may activate a neuronal signaling pathway. Signaling from a strong DAF-1/DAF-4 receptor complex or a weaker DAF-1 receptor alone may provide larvae with more precise control of the dauer/nondauer decision in a range of environmental conditions.

scholarly journals Structural basis for ALK2/BMPR2 receptor complex signaling through kinase domain oligomerization

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Christopher Agnew ◽  
Pelin Ayaz ◽  
Risa Kashima ◽  
Hanna S. Loving ◽  
Prajakta Ghatpande ◽  
...  
Keyword(s):  
Md Simulations ◽  
Kinase Domain ◽  
Structural Basis ◽  
Type I ◽  
Type Ii ◽  
Exchange Mass Spectrometry ◽  
Receptor Complexes ◽  
Bmp Receptors ◽  
Morphogenetic Protein ◽  
Smad Proteins

AbstractUpon ligand binding, bone morphogenetic protein (BMP) receptors form active tetrameric complexes, comprised of two type I and two type II receptors, which then transmit signals to SMAD proteins. The link between receptor tetramerization and the mechanism of kinase activation, however, has not been elucidated. Here, using hydrogen deuterium exchange mass spectrometry (HDX-MS), small angle X-ray scattering (SAXS) and molecular dynamics (MD) simulations, combined with analysis of SMAD signaling, we show that the kinase domain of the type I receptor ALK2 and type II receptor BMPR2 form a heterodimeric complex via their C-terminal lobes. Formation of this dimer is essential for ligand-induced receptor signaling and is targeted by mutations in BMPR2 in patients with pulmonary arterial hypertension (PAH). We further show that the type I/type II kinase domain heterodimer serves as the scaffold for assembly of the active tetrameric receptor complexes to enable phosphorylation of the GS domain and activation of SMADs.

scholarly journals Mechanisms of Transforming Growth Factor-β Receptor Endocytosis and Intracellular Sorting Differ between Fibroblasts and Epithelial Cells

2001 ◽  
Vol 12 (3) ◽  
pp. 675-684 ◽  
Author(s):  
Jules J.E. Doré ◽  
Diying Yao ◽  
Maryanne Edens ◽  
Nandor Garamszegi ◽  
Elizabeth L. Sholl ◽  
...  
Keyword(s):  
Growth Factor ◽  
Epithelial Cells ◽  
Ligand Binding ◽  
Transforming Growth Factor ◽  
Point Mutations ◽  
Type I ◽  
Receptor Complex ◽  
Type Ii ◽  
Down Regulation ◽  
Β Receptor

Transforming growth factor-βs (TGF-β) are multifunctional proteins capable of either stimulating or inhibiting mitosis, depending on the cell type. These diverse cellular responses are caused by stimulating a single receptor complex composed of type I and type II receptors. Using a chimeric receptor model where the granulocyte/monocyte colony-stimulating factor receptor ligand binding domains are fused to the transmembrane and cytoplasmic signaling domains of the TGF-β type I and II receptors, we wished to describe the role(s) of specific amino acid residues in regulating ligand-mediated endocytosis and signaling in fibroblasts and epithelial cells. Specific point mutations were introduced at Y182, T200, and Y249 of the type I receptor and K277 and P525 of the type II receptor. Mutation of either Y182 or Y249, residues within two putative consensus tyrosine-based internalization motifs, had no effect on endocytosis or signaling. This is in contrast to mutation of T200 to valine, which resulted in ablation of signaling in both cell types, while only abolishing receptor down-regulation in fibroblasts. Moreover, in the absence of ligand, both fibroblasts and epithelial cells constitutively internalize and recycle the TGF-β receptor complex back to the plasma membrane. The data indicate fundamental differences between mesenchymal and epithelial cells in endocytic sorting and suggest that ligand binding diverts heteromeric receptors from the default recycling pool to a pathway mediating receptor down-regulation and signaling.

scholarly journals Dynamic Regulation of Caveolin-1 Trafficking in the Germ Line and Embryo of Caenorhabditis elegans

2006 ◽  
Vol 17 (7) ◽  
pp. 3085-3094 ◽  
Author(s):  
Ken Sato ◽  
Miyuki Sato ◽  
Anjon Audhya ◽  
Karen Oegema ◽  
Peter Schweinsberg ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Plasma Membrane ◽  
Caenorhabditis Elegans ◽  
Fluorescent Protein ◽  
Germ Line ◽  
Cortical Granule ◽  
Major Protein ◽  
Dynamic Regulation ◽  
Caveolin 1 ◽  
Green Fluorescent

Caveolin is the major protein component required for the formation of caveolae on the plasma membrane. Here we show that trafficking of Caenorhabditis elegans caveolin-1 (CAV-1) is dynamically regulated during development of the germ line and embryo. In oocytes a CAV-1-green fluorescent protein (GFP) fusion protein is found on the plasma membrane and in large vesicles (CAV-1 bodies). After ovulation and fertilization the CAV-1 bodies fuse with the plasma membrane in a manner reminiscent of cortical granule exocytosis as described in other species. Fusion of CAV-1 bodies with the plasma membrane appears to be regulated by the advancing cell cycle, and not fertilization per se, because fusion can proceed in spe-9 fertilization mutants but is blocked by RNA interference–mediated knockdown of an anaphase-promoting complex component (EMB-27). After exocytosis, most CAV-1-GFP is rapidly endocytosed and degraded within one cell cycle. CAV-1 bodies in oocytes appear to be produced by the Golgi apparatus in an ARF-1–dependent, clathrin-independent, mechanism. Conversely endocytosis and degradation of CAV-1-GFP in embryos requires clathrin, dynamin, and RAB-5. Our results demonstrate that the distribution of CAV-1 is highly dynamic during development and provides new insights into the sorting mechanisms that regulate CAV-1 localization.

scholarly journals The Regularity of Sustained Firing Reveals Two Populations of Slowly Adapting Touch Receptors in Mouse Hairy Skin

2010 ◽  
Vol 103 (6) ◽  
pp. 3378-3388 ◽  
Author(s):  
Scott A. Wellnitz ◽  
Daine R. Lesniak ◽  
Gregory J. Gerling ◽  
Ellen A. Lumpkin
Keyword(s):  
Fluorescent Protein ◽  
Ex Vivo ◽  
Receptive Fields ◽  
Receptor Subtypes ◽  
Type I ◽  
Genetic Dissection ◽  
Merkel Cells ◽  
Simple Method ◽  
Green Fluorescent ◽  
Nerve Recordings

Touch is initiated by diverse somatosensory afferents that innervate the skin. The ability to manipulate and classify receptor subtypes is prerequisite for elucidating sensory mechanisms. Merkel cell–neurite complexes, which distinguish shapes and textures, are experimentally tractable mammalian touch receptors that mediate slowly adapting type I (SAI) responses. The assessment of SAI function in mutant mice has been hindered because previous studies did not distinguish SAI responses from slowly adapting type II (SAII) responses, which are thought to arise from different end organs, such as Ruffini endings. Thus we sought methods to discriminate these afferent types. We developed an epidermis-up ex vivo skin–nerve chamber to record action potentials from afferents while imaging Merkel cells in intact receptive fields. Using model-based cluster analysis, we found that two types of slowly adapting receptors were readily distinguished based on the regularity of touch-evoked firing patterns. We identified these clusters as SAI (coefficient of variation = 0.78 ± 0.09) and SAII responses (0.21 ± 0.09). The identity of SAI afferents was confirmed by recording from transgenic mice with green fluorescent protein–expressing Merkel cells. SAI receptive fields always contained fluorescent Merkel cells ( n = 10), whereas SAII receptive fields lacked these cells ( n = 5). Consistent with reports from other vertebrates, mouse SAI and SAII responses arise from afferents exhibiting similar conduction velocities, receptive field sizes, mechanical thresholds, and firing rates. These results demonstrate that mice, like other vertebrates, have two classes of slowly adapting light-touch receptors, identify a simple method to distinguish these populations, and extend the utility of skin–nerve recordings for genetic dissection of touch receptor mechanisms.

scholarly journals Vaccinia Virus F13L Protein with a Conserved Phospholipase Catalytic Motif Induces Colocalization of the B5R Envelope Glycoprotein in Post-Golgi Vesicles

2001 ◽  
Vol 75 (16) ◽  
pp. 7528-7542 ◽  
Author(s):  
Matloob Husain ◽  
Bernard Moss
Keyword(s):  
Vaccinia Virus ◽  
Fluorescent Protein ◽  
Plasmid Vector ◽  
Recombinant Vaccinia Virus ◽  
Open Reading Frames ◽  
Type I ◽  
Golgi Vesicles ◽  
Infected Cells ◽  
Catalytic Motif ◽  
Green Fluorescent

ABSTRACT The wrapping of intracellular mature vaccinia virions by modifiedtrans-Golgi or endosomal cisternae to form intracellular enveloped virions is dependent on at least two viral proteins encoded by the B5R and F13L open reading frames. B5R is a type I integral membrane glycoprotein, whereas F13L is an unglycosylated, palmitylated protein with a motif that is conserved in a superfamily of phospholipid-metabolizing enzymes. Microscopic visualization of the F13L protein was achieved by fusing it to the enhanced green fluorescent protein (GFP). F13L-GFP was functional when expressed by a recombinant vaccinia virus in which it replaced the wild-type F13L gene or by transfection of uninfected cells with a plasmid vector followed by infection with an F13L deletion mutant. In uninfected or infected cells, F13L-GFP was associated with Golgi cisternae and post-Golgi vesicles containing the LAMP 2 late endosomal-lysosomal marker. Association of F13L-GFP with vesicles was dependent on an intact phospholipase catalytic motif and sites of palmitylation. The B5R protein was also associated with LAMP2-containing vesicles when F13L-GFP was coexpressed, but was largely restricted to Golgi cisternae in the absence of F13L-GFP or when the F13L moiety was mutated. We suggest that the F13L protein, like its human phospholipase D homolog, regulates vesicle formation and that this process is involved in intracellular enveloped virion membrane formation.

scholarly journals Identification of a Lysosomal Pathway Regulating Degradation of the Bone Morphogenetic Protein Receptor Type II

2010 ◽  
Vol 285 (48) ◽  
pp. 37641-37649 ◽  
Author(s):  
Hannah J. Durrington ◽  
Paul D. Upton ◽  
Simon Hoer ◽  
Jessica Boname ◽  
Benjamin J. Dunmore ◽  
...  
Keyword(s):  
Bone Morphogenetic Protein ◽  
Receptor Type ◽  
Type Ii ◽  
Bone Morphogenetic Protein Receptor ◽  
Protein Receptor ◽  
Morphogenetic Protein

Asymmetrical targeting of type II Na-Picotransporters in renal and intestinal epithelial cell lines

2000 ◽  
Vol 278 (3) ◽  
pp. F361-F368 ◽  
Author(s):  
N. Hernando ◽  
S. Sheikh ◽  
Z. Karim-Jimenez ◽  
H. Galliker ◽  
J. Forgo ◽  
...  
Keyword(s):  
Epithelial Cell ◽  
Cell Lines ◽  
Fluorescent Protein ◽  
Intestinal Epithelial ◽  
Type Ii ◽  
Opossum Kidney ◽  
Epithelial Cell Lines ◽  
Molecular Determinants ◽  
Cellular Context ◽  
Green Fluorescent

Targeting of newly synthesized transporters to either the apical or basolateral domains of polarized cells is crucial for the function of epithelia, such as in the renal proximal tubule or in the small intestine. Recently, different sodium-phosphate cotransporters have been identified. Type II cotransporters can be subdivided into two groups: type IIa and type IIb. Type IIa is predominantly expressed in renal proximal tubules, whereas type IIb is located on the intestinal and lung epithelia. To gain some insights into the polarized targeting of the type II cotransporters, we have transiently expressed type IIa and type IIb cotransporters in several epithelial cell lines: two lines derived from renal proximal cells (opossum kidney and LLC-PK1), one from renal distal cells (Madin-Darby canine kidney), and one from colonic epithelium (CaCo-2). We studied the expression of the transporters fused to the enhanced green fluorescent protein. Our data indicate that the polarized targeting is dependent on molecular determinants most probably located at the COOH terminus of the cotransporters as well as on the cellular context.

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