The endoplasmic reticulum (ER) represents the largest continuous tubular membrane network within nucleated mammalian cells.
Sec61, termed SecYEG in prokaryotes, is a membrane protein complex found in all domains of life. As the core component of the translocon, it transports proteins to the endoplasmic reticulum in eukaryotes and out of the cell in prokaryotes. It is a doughnut-shaped pore through the membrane with 3 different subunits (heterotrimeric), SecY (α), SecE (γ), and SecG (β). It has a region called the plug that blocks transport into or out of the ER. This plug is displaced when the hydrophobic region of a nascent polypeptide interacts with another region of Sec61 called the seam, allowing translocation of the polypeptide into the ER lumen. This ensemble of proteins facilitates ER targeting of precursor polypeptides, modification of precursor polypeptides in transit through the Sec61 complex, and Sec61 channel gating, i.e., dynamic regulation of the pore forming subunit to mediate precursor transport and calcium efflux. Here you can see a recent cryo-EM structure of the human Sec61 complex (PDB code: 8DNY)
#molecularart ... #immolecular ... #endoplasmic ... #reticulum ... #complex ... #translocon ... #sec61 ... #cryoem
Structure rendered with @proteinimaging and depicted with @corelphotopaint
Sec61, termed SecYEG in prokaryotes, is a membrane protein complex found in all domains of life. As the core component of the translocon, it transports proteins to the endoplasmic reticulum in eukaryotes and out of the cell in prokaryotes. It is a doughnut-shaped pore through the membrane with 3 different subunits (heterotrimeric), SecY (α), SecE (γ), and SecG (β). It has a region called the plug that blocks transport into or out of the ER. This plug is displaced when the hydrophobic region of a nascent polypeptide interacts with another region of Sec61 called the seam, allowing translocation of the polypeptide into the ER lumen. This ensemble of proteins facilitates ER targeting of precursor polypeptides, modification of precursor polypeptides in transit through the Sec61 complex, and Sec61 channel gating, i.e., dynamic regulation of the pore forming subunit to mediate precursor transport and calcium efflux. Here you can see a recent cryo-EM structure of the human Sec61 complex (PDB code: 8DNY)
#molecularart ... #immolecular ... #endoplasmic ... #reticulum ... #complex ... #translocon ... #sec61 ... #cryoem
Structure rendered with @proteinimaging and depicted with @corelphotopaint
