TY - JOUR
T1 - The nucleolar channel system of human endometrium is related to endoplasmic reticulum and R-rings
AU - Kittur, Nupur
AU - Zapantis, Gregory
AU - Aubuchon, Mira
AU - Santoro, Nanette
AU - Bazett-Jones, David P.
AU - Meier, U. Thomas
PY - 2007/6
Y1 - 2007/6
N2 - The nucleolar channel system (NCS) is a well-established ultrastructural hallmark of the postovulation endometrium. Its transient presence has been associated with human fertility. Nevertheless, the biogenesis, composition, and function of these intranuclear membrane cisternae are unknown. Membrane systems with a striking ultrastructural resemblance to the NCS, termed R-rings, are induced in nuclei of tissue culture cells by overexpression of the central repeat domain of the nucleolar protein Nopp140. Here we provide a first molecular characterization of the NCS and compare the biogenesis of these two enigmatic organelles. Like the R-rings, the NCS consists of endoplasmic reticulum harboring the marker glucose-6-phosphatase. R-ring formation initiates at the nuclear envelope, apparently by a calcium-mediated Nopp140-membrane interaction, as supported by the calcium-binding ability of Nopp140, the inhibition of R-ring formation by calcium chelators, and the concentration of Nopp140 and complexed calcium in R-rings. Although biogenesis of the NCS may initiate similarly, the reduced presence of complexed calcium and Nopp140 suggests the involvement of additional factors.
AB - The nucleolar channel system (NCS) is a well-established ultrastructural hallmark of the postovulation endometrium. Its transient presence has been associated with human fertility. Nevertheless, the biogenesis, composition, and function of these intranuclear membrane cisternae are unknown. Membrane systems with a striking ultrastructural resemblance to the NCS, termed R-rings, are induced in nuclei of tissue culture cells by overexpression of the central repeat domain of the nucleolar protein Nopp140. Here we provide a first molecular characterization of the NCS and compare the biogenesis of these two enigmatic organelles. Like the R-rings, the NCS consists of endoplasmic reticulum harboring the marker glucose-6-phosphatase. R-ring formation initiates at the nuclear envelope, apparently by a calcium-mediated Nopp140-membrane interaction, as supported by the calcium-binding ability of Nopp140, the inhibition of R-ring formation by calcium chelators, and the concentration of Nopp140 and complexed calcium in R-rings. Although biogenesis of the NCS may initiate similarly, the reduced presence of complexed calcium and Nopp140 suggests the involvement of additional factors.
UR - http://www.scopus.com/inward/record.url?scp=34250337757&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=34250337757&partnerID=8YFLogxK
U2 - 10.1091/mbc.E07-02-0154
DO - 10.1091/mbc.E07-02-0154
M3 - Article
C2 - 17429075
AN - SCOPUS:34250337757
SN - 1059-1524
VL - 18
SP - 2296
EP - 2304
JO - Molecular biology of the cell
JF - Molecular biology of the cell
IS - 6
ER -