About: The first membrane-spanning domain (m1) of the M glycoprotein of avian coronavirus (formerly called E1) is sufficient to retain this protein in the cis-Golgi. When the membrane-spanning domain of a protein which is efficiently delivered to the plasma membrane (VSV G protein) is replaced with m1, the resulting chimera (Gm1) is retained in the Golgi (Swift, A. M., and C. E. Machamer. 1991. J. Cell Biol. 115:19-30). When assayed in sucrose gradients, we observed that Gm1 formed a large oligomer, and that much of this oligomer was SDS resistant and stayed near the top of the stacking gel of an SDS-polyacrylamide gel. The unusual stability of the oligomer allowed it to be detected easily. Gm1 mutants with single amino acid substitutions in the m1 domain that were retained in the Golgi complex formed SDS-resistant oligomers, whereas mutants that were rapidly released to the plasma membrane did not. Oligomerization was not detected immediately after synthesis of Gm1, but occurred gradually with a lag of approximately 10 min, suggesting that it is not merely aggregation of misfolded proteins. Furthermore, oligomerization did not occur under several conditions that block ER to Golgi transport. The lumenal domain was not required for oligomerization since another chimera (alpha m1G), where the lumenal domain of Gm1 was replaced by the alpha subunit of human chorionic gonadotropin, also formed an SDS-resistant oligomer, and was able to form hetero-oligomers with Gm1 as revealed by coprecipitation experiments. SDS resistance was conferred by the cytoplasmic tail of VSV G, because proteolytic digestion of the tail in microsomes containing Gm1 oligomers resulted in loss of SDS resistance, although the protease-treated material continued to migrate as a large oligomer on sucrose gradients. Interestingly, treatment of cells with cytochalasin D blocked formation of SDS-resistant (but not SDS- sensitive) oligomers. Our data suggest that SDS-resistant oligomers form as newly synthesized molecules of Gm1 arrive at the Golgi complex and may interact (directly or indirectly) with an actin-based cytoskeletal matrix. The oligomerization of Gm1 and other resident proteins could serve as a mechanism for their retention in the Golgi complex.   Goto Sponge  NotDistinct  Permalink

An Entity of Type : fabio:Abstract, within Data Space : wasabi.inria.fr associated with source document(s)

AttributesValues
type
value
  • The first membrane-spanning domain (m1) of the M glycoprotein of avian coronavirus (formerly called E1) is sufficient to retain this protein in the cis-Golgi. When the membrane-spanning domain of a protein which is efficiently delivered to the plasma membrane (VSV G protein) is replaced with m1, the resulting chimera (Gm1) is retained in the Golgi (Swift, A. M., and C. E. Machamer. 1991. J. Cell Biol. 115:19-30). When assayed in sucrose gradients, we observed that Gm1 formed a large oligomer, and that much of this oligomer was SDS resistant and stayed near the top of the stacking gel of an SDS-polyacrylamide gel. The unusual stability of the oligomer allowed it to be detected easily. Gm1 mutants with single amino acid substitutions in the m1 domain that were retained in the Golgi complex formed SDS-resistant oligomers, whereas mutants that were rapidly released to the plasma membrane did not. Oligomerization was not detected immediately after synthesis of Gm1, but occurred gradually with a lag of approximately 10 min, suggesting that it is not merely aggregation of misfolded proteins. Furthermore, oligomerization did not occur under several conditions that block ER to Golgi transport. The lumenal domain was not required for oligomerization since another chimera (alpha m1G), where the lumenal domain of Gm1 was replaced by the alpha subunit of human chorionic gonadotropin, also formed an SDS-resistant oligomer, and was able to form hetero-oligomers with Gm1 as revealed by coprecipitation experiments. SDS resistance was conferred by the cytoplasmic tail of VSV G, because proteolytic digestion of the tail in microsomes containing Gm1 oligomers resulted in loss of SDS resistance, although the protease-treated material continued to migrate as a large oligomer on sucrose gradients. Interestingly, treatment of cells with cytochalasin D blocked formation of SDS-resistant (but not SDS- sensitive) oligomers. Our data suggest that SDS-resistant oligomers form as newly synthesized molecules of Gm1 arrive at the Golgi complex and may interact (directly or indirectly) with an actin-based cytoskeletal matrix. The oligomerization of Gm1 and other resident proteins could serve as a mechanism for their retention in the Golgi complex.
subject
  • Organelles
  • Cooking weights and measures
  • Membrane biology
  • Orders, decorations, and medals of Sri Lanka
part of
is abstract of
is hasSource of
Faceted Search & Find service v1.13.91 as of Mar 24 2020


Alternative Linked Data Documents: Sponger | ODE     Content Formats:       RDF       ODATA       Microdata      About   
This material is Open Knowledge   W3C Semantic Web Technology [RDF Data]
OpenLink Virtuoso version 07.20.3229 as of Jul 10 2020, on Linux (x86_64-pc-linux-gnu), Single-Server Edition (94 GB total memory)
Data on this page belongs to its respective rights holders.
Virtuoso Faceted Browser Copyright © 2009-2025 OpenLink Software