The relationship between the nuclear membranes and the endoplasmic reticulum in interphase cells

Richardson, J.C.; Agutter, Paul S.

doi:10.1042/bst0080459

Cited by 17 publications

(9 citation statements)

References 27 publications

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“…5). Perhaps our most striking finding, considering that the nuclear membrane is continuous with the ER and that these membrane systems are evolutionarily conserved (46), is that the prominent 68-and 30-kDa proteins labeled by [a-32P]GTP in ER (30) are undetectable in the NE fractions.…”

Section: Resultsmentioning

confidence: 96%

GTP-binding proteins in rat liver nuclear envelopes.

Rubins

Benditt

Dickey

et al. 1990

Proc. Natl. Acad. Sci. U.S.A.

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Nuclear transport as well as reassembly of the nuclear envelope (NE) after completion of mitosis are processes that have been shown to require GTP and ATP. To study the presence and localization of GTP-binding proteins with apparent molecular masses of 140, 53, 47, 33, and 31 kDa. All GTP-binding proteins appear to localize preferentially to the inner nuclear membrane, possibly to the interface between inner nuclear membrane and lamina. Despite the evolutionary conservation between the NE and the rough endoplasmic reticulum, the GTP-binding proteins identified differed between these two compartments. Most notably, the 68-and 30-kDa GTP-binding subunits of the signal recognition particle receptor, which photolabeled with [a-32P]GTP in the rough endoplasmic reticulum fraction, were totally excluded from the NE fraction. Conversely, a major 53-kDa photolabeled protein in the NE was absent from rough endoplasmic reticulum. Whereas Western-blotted NE proteins bound GTP specifically, all [a-32P]GTP photolabeled proteins could be blocked by competition with ATP, although with a competition profile that differed from that obtained with GTP. In comparative crosslinking studies with [a-32P]ATP, we have Identified three specific ATP-binding proteins with molecular masses of 160, 78, and 74 kDa. The localization of GTP-and ATPbinding proteins within the NE appears appropriate for their involvement in nuclear transport and in the GTP-dependent fusion of nuclear membrane vesicles required for reassembly of the nucleus after mitosis.The nuclear envelope (NE) is a distinct intracellular structure, consisting of an outer membrane continuous with the endoplasmic reticulum (ER), an inner membrane facing the nucleoplasm, the lamina, and pore complexes (1). As a barrier between the nuclear and the cytoplasmic compartments, the NE is involved in the regulated transport of protein and RNA. These transport processes have been shown to require energy and to depend on specific receptor and transport proteins associated with the NE (2-9). Workers in several laboratories have described rather nonspecific adenosine triphosphatases (ATPases) in the NE, which can bind and hydrolyze both ATP and GTP, and, to a lesser extent, also UTP, CTP, and deoxynucleoside triphosphates (10)(11)(12).In most cells, the NE disassembles and reassembles during mitosis, and the recent development of in vitro systems has permitted a more detailed study of the assembly process (13-16). In these systems, the initial event in the re-formation of the NE at the end of mitosis involves the targeting of nuclear membrane vesicles to the surface of chromatin. Subsequent fusion of these membrane vesicles requires both GTP and ATP, and results in the formation of a doublemembrane complex that is apparently identical to that surrounding normal nuclei (17). In this regard, the process of nuclear membrane fusion resembles GTP-dependent fusion processes in other cellular membrane systems, such as the ER and the Golgi, and may be regulated by GTP-binding proteins. GTP-...

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Section: Resultsmentioning

confidence: 96%

GTP-binding proteins in rat liver nuclear envelopes.

Rubins

Benditt

Dickey

et al. 1990

Proc. Natl. Acad. Sci. U.S.A.

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“…The nuclear envelope is comprised of an inner membrane, which abuts the nucleoplasm, and an outer membrane, which is continuous with the endoplasmic reticulum (ER). Together, the two membranes and their aqueous lumen are known as the envelope [2] and have an inner environment similar to that of the ER [3]. Anchored within this envelope are the nuclear pore complexes (NPCs) [4] long considered the only route between the cytosol and nucleoplasm.…”

Section: The Nucleus and The Nuclear Envelopementioning

confidence: 99%

“…Each will be examined separately. 3 . This appeared to be from nonmitochondrial, ATP-dependent stores.…”

Section: Factors Which Control Cytosolic Calciummentioning

confidence: 99%

“…For IP 3 and IP 4 to have an effect within the nucleus itself, there must be specific binding sites/calcium channels mediated by these compounds. The information available on these topics should be viewed with care since all reports used isolated nuclei and most are from the same laboratory.…”

Section: The Nuclear Ip 3 and Ip 4 Binding Sitesmentioning

confidence: 99%

“…This appeared to be from nonmitochondrial, ATP-dependent stores. IP 3 formation occurs in vivo from the breakdown of PIP 2 by the enzyme phospholipase C. This occurs through a G protein-mediated mechanism [34]. IP 3 then diffuses out of the membrane to target distinct receptors and causes Ca 2+ release in both muscle [35,36] and non-muscle cells [37].…”

Section: Factors Which Control Cytosolic Calciummentioning

confidence: 99%

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Nuclear Calcium: Transfer to and from the Cytosol

Macdonald¹

1998

Biol Signals Recept

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Although the cell nucleus is known to control much of cell function, little is known as to the mediator of such function. Recent evidence has suggested that Ca²⁺ may be responsible for the regulation of many nuclear events. Early investigations have reported that the nucleus may be able to control its calcium function independently of the adjacent cytosol. IP₃ and IP₄ may act as regulators of nuclear Ca²⁺ independently or in parallel with the cytosol. This paper examines the current state of knowledge regarding nuclear calcium regulation. Additionally, a model for this regulation is proposed.

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Ultrastructural and morphometric analysis of nuclear and nuclear changes during the early growth period in hamster facial neurons

Clark

Jones

LaVelle

1990

J of Comparative Neurology

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In this study, progressive developmental changes in the nucleus and associated organelles, including the nucleolus, coiled bodies, nuclear envelope, and nucleoplasm, of hamster facial motor neurons were characterized by two parallel analyses: ultrastructural and morphometric. Golden hamsters (Mesocricetus auratus) used for this series were the 14-day fetus, newborn (less than 6 hr), and 1, 2, 3, 4, 5, 7, 9, 11 and 13 days postnatal ages, with 3 animals per group. Following anesthesia and perfusion fixation, facial nuclear groups were dissected and processed for electron microscopy. Electron micrographs and camera lucida tracings of nuclear profiles were collected and analyzed. The ultrastructural analysis revealed progressive changes in the nucleolus from a compact, segregated type to a reticulated form characteristic of actively protein-secreting cells. Nucleolar microbodies and fibrillar centers were seen at all ages; the latter structures appeared to decrease in size and increase with age in the series. The nucleolus-associated chromatin became less condensed, suggesting an increase in the incorporation of rDNA into the nucleolus proper. Coiled bodies, both free and attached to nucleoli, were found in varying frequencies. The nucleoplasm of neurons at the earliest stages contained large numbers of heterochromatin clumps, which decreased concomitantly with an increase in interchromatin granules and fibrils during the later stages. Nuclear envelope invaginations, polarized along one side of the nucleus, increased throughout the developmental period examined. These changes occurred in concert with a 61% increase in nuclear size and a 47% increase in the length of nuclear envelope. The sequence of nuclear changes observed during this early period of normal facial neuronal growth completes the study of a series of distinctly defined cytomorphic events in this cell type, the lability of which can be experimentally tested for their functional roles in neuronal development.

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The relationship between the nuclear membranes and the endoplasmic reticulum in interphase cells

Abstract: intracellular membranes in that cell type, rather than a property peculiar to the two systems under consideration. Thus any indication of similarity must be viewed critically in the light of studies on other membranes.

Cited by 17 publications

References 27 publications

GTP-binding proteins in rat liver nuclear envelopes.

GTP-binding proteins in rat liver nuclear envelopes.

Nuclear Calcium: Transfer to and from the Cytosol

Ultrastructural and morphometric analysis of nuclear and nuclear changes during the early growth period in hamster facial neurons

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