scholarly journals FAM209 associates with DPY19L2 and is required for sperm acrosome biogenesis and fertility in mice

2021 ◽  
Author(s):  
Julio M. Castaneda ◽  
Keisuke Shimada ◽  
Yuhkoh Satouh ◽  
Zhifeng Yu ◽  
Masahito Ikawa ◽  
...  
Keyword(s):  
Nuclear Membrane ◽  
Proteomic Analysis ◽  
Transmembrane Protein ◽  
Sequence Similarity ◽  
Rare Condition ◽  
Mouse Sperm ◽  
Inner Nuclear Membrane ◽  
Infertile Men ◽  
Human And Mouse

Infertility afflicts up to 15% of couples globally each year with men a contributing factor in half of these cases. Globozoospermia is a rare condition found in infertile men that is characterized by defective acrosome biogenesis leading to the production of round shaped sperm. Here, we report a novel gene, Fam209 (Family with sequence similarity 209), that is required for acrosome biogenesis in mouse sperm. FAM209 is a small transmembrane protein conserved among mammals. Loss of Fam209 result in fertility defects secondary to abnormalities in acrosome biogenesis during spermiogenesis reminiscent of globozoospermia. Proteomic analysis of the FAM209 proteome identified DPY19L2, a protein involved in the majority of globozoospermia cases. While mutations in human and mouse DPY19L2 have been shown to cause globozoospermia, no in vivo interacting partners of DPY19L2 have been identified until now. FAM209 colocalizes with DPY19L2 to the inner nuclear membrane to maintain the developing acrosome. This report identifies FAM209 as the first interacting partner of DPY19L2 and the second protein that is essential for acrosome biogenesis and that co-localizes with DPY19L2 to the inner nuclear membrane.

scholarly journals The CaaX motif is required for isoprenylation, carboxyl methylation, and nuclear membrane association of lamin B2.

1991 ◽  
Vol 113 (1) ◽  
pp. 13-23 ◽  
Author(s):  
G T Kitten ◽  
E A Nigg
Keyword(s):  
Nuclear Membrane ◽  
Stop Codon ◽  
Mevalonic Acid ◽  
Cysteine Residue ◽  
Inner Nuclear Membrane ◽  
Nuclear Lamins ◽  
Carboxyl Methylation ◽  
Reticulocyte Lysates ◽  
Caax Motif

Recent evidence suggests that the conserved COOH-terminal CaaX motif of nuclear lamins may play a role in targeting newly synthesized proteins to the nuclear envelope. We have shown previously that in rabbit reticulocyte lysates the cysteine residue of the CaaX motif of chicken lamin B2 is necessary for incorporation of a derivative of mevalonic acid, the precursor of isoprenoids. Here we have analyzed the properties of normal and mutated forms of chicken lamin B2 stably expressed in mouse L cells. Mutation of the cysteine residue of the CaaX motif to alanine or introduction of a stop codon immediately after the cysteine residue was found to abolish both isoprenylation and carboxyl methylation of transfected lamin B2. Concomitantly, although nuclear import of the mutant lamin B2 proteins was preserved, their association with the inner nuclear membrane was severely impaired. From these results we conclude that the COOH-terminal CaaX motif is required for isoprenylation and carboxyl methylation of lamins in vivo, and that these modifications are important for association of B-type lamins with the nucleoplasmic surface of the inner nuclear membrane.

scholarly journals Internuclear exchange of an inner nuclear membrane protein (p55) in heterokaryons: in vivo evidence for the interaction of p55 with the nuclear lamina.

1990 ◽  
Vol 111 (6) ◽  
pp. 2225-2234 ◽  
Author(s):  
L Powell ◽  
B Burke
Keyword(s):  
Nuclear Membrane ◽  
Lateral Diffusion ◽  
Nuclear Lamina ◽  
Membrane System ◽  
Mouse Cell ◽  
Nuclear Pore ◽  
Nuclear Pore Complexes ◽  
Inner Nuclear Membrane ◽  
Pore Complexes

The movement between nuclei of an integral protein of the inner nuclear membrane has been studied in rat/mouse and rat/hamster heterokaryons. This protein, p55, was found to equilibrate between nuclei over a period of approximately 6 h in the absence of new protein synthesis. When rat/mouse heterokaryons were constructed using an undifferentiated murine embryonal carcinoma (P19), which lacks lamins A and C, no accumulation of p55 in the mouse cell nucleus was observed. However, P19 nuclei could be rendered competent to accumulate p55 by transfecting the parent cells with human lamin A before cell fusion, supporting the notion that p55 may interact with the nuclear lamina. Since p55 does not appear to be able to dissociate from the nuclear membrane, it is concluded that this exchange between nuclei does not occur in the aqueous phase and instead is probably membrane mediated. It is proposed that this protein may be free to move between the inner and outer nuclear membranes via the continuities at the nuclear pore complexes and that transfer between nuclei occurs via lateral diffusion through the peripheral ER, which appears to form a single continuous membrane system in these heterokaryons. One implication of these observations is that accumulation of at least some integral proteins in the inner nuclear membrane may be mediated by interactions with other nuclear components and may not require a single defined targeting sequence.

scholarly journals Membrane-anchored growth factor, HB-EGF, on the cell surface targeted to the inner nuclear membrane

2008 ◽  
Vol 180 (4) ◽  
pp. 763-769 ◽  
Author(s):  
Miki Hieda ◽  
Mayumi Isokane ◽  
Michiko Koizumi ◽  
Chiduru Higashi ◽  
Taro Tachibana ◽  
...  
Keyword(s):  
Growth Factor ◽  
Cell Surface ◽  
Nuclear Envelope ◽  
Nuclear Membrane ◽  
Transmembrane Protein ◽  
Active Form ◽  
Type I ◽  
Transcriptional Repressors ◽  
Sequence Element ◽  
Inner Nuclear Membrane

Heparin-binding EGF-like growth factor (HB-EGF) is synthesized as a type I transmembrane protein (proHB-EGF) and expressed on the cell surface. The ectodomain shedding of proHB-EGF at the extracellular region on the plasma membrane yields a soluble EGF receptor ligand and a transmembrane-cytoplasmic fragment (HB-EGF-CTF). The cytoplasmic domain of proHB-EGF (HB-EGF-cyto) interacts with transcriptional repressors to reverse their repressive activities. However, how HB-EGF-cyto accesses transcriptional repressors is yet unknown. The present study demonstrates that, after exposure to shedding stimuli, both HB-EGF-CTF and unshed proHB-EGF translocate to the nuclear envelope. Immunoelectron microscopy and digitonin-permeabilized cells showed that HB-EGF-cyto signals are at the inner nuclear membrane. A short sequence element within the HB-EGF-cyto allows a transmembrane protein to localize to the nuclear envelope. The dominant-active form of Rab5 and Rab11 suppressed nuclear envelope targeting. Collectively, these data demonstrate that membrane-anchored HB-EGF is targeted to the inner nuclear membrane via a retrograde membrane trafficking pathway.

scholarly journals Efficient protein targeting to the inner nuclear membrane requires Atlastin-dependent maintenance of ER topology

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Sumit Pawar ◽  
Rosemarie Ungricht ◽  
Peter Tiefenboeck ◽  
Jean-Christophe Leroux ◽  
Ulrike Kutay
Keyword(s):  
Nuclear Membrane ◽  
Protein Targeting ◽  
Membrane System ◽  
Nuclear Pore ◽  
Nuclear Pore Complexes ◽  
Vitro Assay ◽  
Inner Nuclear Membrane ◽  
General Importance

Newly synthesized membrane proteins are targeted to the inner nuclear membrane (INM) by diffusion within the membrane system of the endoplasmic reticulum (ER), translocation through nuclear pore complexes (NPCs) and retention on nuclear partners. Using a visual in vitro assay we previously showed that efficient protein targeting to the INM depends on nucleotide hydrolysis. We now reveal that INM targeting is GTP-dependent. Exploiting in vitro reconstitution and in vivo analysis of INM targeting, we establish that Atlastins, membrane-bound GTPases of the ER, sustain the efficient targeting of proteins to the INM by their continued activity in preserving ER topology. When ER topology is altered, the long-range diffusional exchange of proteins in the ER network and targeting efficiency to the INM are diminished. Highlighting the general importance of proper ER topology, we show that Atlastins also influence NPC biogenesis and timely exit of secretory cargo from the ER.

scholarly journals Inner-Nuclear-Membrane-Associated Degradation Employs Dfm1-Independent Retrotranslocation and Alleviates Misfolded Transmembrane-Protein Toxicity

2021 ◽  
pp. mbc.E20-11-0720
Author(s):  
Matthew P. Flagg ◽  
Margaret A. Wangeline ◽  
Sarah R. Holland ◽  
Sascha H. Duttke ◽  
Christopher Benner ◽  
...  
Keyword(s):  
Lipid Bilayers ◽  
Nuclear Membrane ◽  
Transmembrane Protein ◽  
Transmembrane Proteins ◽  
Extraction Process ◽  
26S Proteasome ◽  
Energetic Cost ◽  
Inner Nuclear Membrane ◽  
Transmembrane Segments ◽  
Protein Toxicity

Prior to their delivery to and degradation by the 26S proteasome, misfolded transmembrane proteins of the ER and inner-nuclear membrane must be extracted from lipid bilayers. This extraction process, known as retrotranslocation, requires both quality-control E3 ubiquitin ligases and dislocation factors that diminish the energetic cost of dislodging the transmembrane segments of a protein. Recently, we showed that retrotranslocation of all ER transmembrane proteins requires the Dfm1 rhomboid pseudoprotease. However, we did not investigate whether Dfm1 also mediated retrotranslocation of transmembrane substrates in the inner-nuclear membrane (INM), which is contiguous with the ER but functionally separated from it by nucleoporins. Here, we show that canonical retrotranslocation occurs during INM-associated degradation (INMAD) but proceeds independently of Dfm1. Despite this independence, ERAD-M and INMAD cooperate to mitigate proteotoxicity. We show a novel misfolded-transmembrane-protein toxicity that elicits genetic suppression, demonstrating the cell's ability to tolerate a toxic burden of misfolded transmembrane proteins without functional INMAD or ERAD-M. This strikingly contrasted the suppression of the dfm1Δ null, which leads to the resumption of ERAD-M through HRD-complex remodeling. Thus, we conclude that INM retrotranslocation proceeds through a novel, private channel, which can be studied by virtue of its role in alleviating membrane-associated proteotoxicity.

scholarly journals Samp1, a RanGTP binding transmembrane protein in the inner nuclear membrane

Nucleus ◽  
2016 ◽  
Vol 7 (4) ◽  
pp. 415-423 ◽  
Author(s):  
Balaje Vijayaraghavan ◽  
Mohammed Hakim Jafferali ◽  
Ricardo A. Figueroa ◽  
Einar Hallberg
Keyword(s):  
Nuclear Membrane ◽  
Transmembrane Protein ◽  
Inner Nuclear Membrane

scholarly journals Characterization of A 54-kD protein of the inner nuclear membrane: evidence for cell cycle-dependent interaction with the nuclear lamina.

1991 ◽  
Vol 114 (3) ◽  
pp. 389-400 ◽  
Author(s):  
S M Bailer ◽  
H M Eppenberger ◽  
G Griffiths ◽  
E A Nigg
Keyword(s):  
Cell Cycle ◽  
Nuclear Envelope ◽  
Nuclear Membrane ◽  
Cultured Cells ◽  
Nuclear Lamina ◽  
Biochemical Properties ◽  
Inner Nuclear Membrane ◽  
Cycle Dependent ◽  
Mitotic Phosphorylation

Using a mAb (R-7), we have characterized a 54-kD protein of the chicken nuclear envelope. Based on its biochemical properties and subnuclear distribution p54 is likely to be an integral membrane component specific to the inner nuclear membrane. Fractionation experiments indicate that p54 interacts, directly or indirectly, with the nuclear lamina, and analysis of p54 in cultured cells suggests that this interaction is controlled by cell cycle-dependent posttranslational modification, most likely phosphorylation. Modification of p54 results in a slightly reduced electrophoretic mobility, and it converts the protein from a detergent-resistant to a detergent-extractable form. Detergent solubilization of p54 can be induced in vivo by treating isolated nuclei or nuclear envelopes with highly purified cdc2 kinase, one of the most prominent kinases active in mitotic cells. These results suggest that mitotic phosphorylation of p54 might contribute to control nuclear envelope dynamics during mitosis in vivo.

scholarly journals Myne-1, a spectrin repeat transmembrane protein of the myocyte inner nuclear membrane, interacts with lamin A/C

2002 ◽  
Vol 115 (1) ◽  
pp. 61-70 ◽  
Author(s):  
John M. K. Mislow ◽  
Marian S. Kim ◽  
Dawn Belt Davis ◽  
Elizabeth M. McNally
Keyword(s):  
Muscular Dystrophy ◽  
Nuclear Envelope ◽  
Nuclear Membrane ◽  
Transmembrane Domain ◽  
Transmembrane Protein ◽  
Lamin A ◽  
Spectrin Repeat ◽  
Inner Nuclear Membrane ◽  
C Terminus

Mutations in the genes encoding the inner nuclear membrane proteins lamin A/C and emerin produce cardiomyopathy and muscular dystrophy in humans and mice. The mechanism by which these broadly expressed gene products result in tissue-specific dysfunction is not known. We have identified a protein of the inner nuclear membrane that is highly expressed in striated and smooth muscle. This protein, myne-1 (myocyte nuclear envelope), is predicted to have seven spectrin repeats, an interrupted LEM domain and a single transmembrane domain at its C-terminus. We found that myne-1 is expressed upon early muscle differentiation in multiple intranuclear foci concomitant with lamin A/C expression. In mature muscle, myne-1 and lamin A/C are perfectly colocalized, although colocalization with emerin is only partial. Moreover, we show that myne-1 and lamin A/C coimmunoprecipitate from differentiated muscle in vitro. The muscle-specific inner nuclear envelope expression of myne-1, along with its interaction with lamin A/C, indicates that this gene is a potential mediator of cardiomyopathy and muscular dystrophy.

LBR, a chromatin and lamin binding protein from the inner nuclear membrane, is proteolyzed at late stages of apoptosis

1998 ◽  
Vol 111 (10) ◽  
pp. 1441-1451 ◽  
Author(s):  
I. Duband-Goulet ◽  
J.C. Courvalin ◽  
B. Buendia
Keyword(s):  
Nuclear Membrane ◽  
Binding Protein ◽  
Transmembrane Protein ◽  
Chromatin Condensation ◽  
Lamin B ◽  
Inner Nuclear Membrane ◽  
Amino Terminal ◽  
Terminal Domain ◽  
Amino Terminal Domain ◽  
Late Stages

Chromatin condensation and apposition to the nuclear envelope is an important feature of the execution phase of apoptosis. During this process, lamin proteins that are located between the inner nuclear membrane and heterochromatin are proteolyzed by the apoptosis-specific protease caspase 6. We have investigated the fate of nuclear membranes during apoptosis by studying the lamin B receptor (LBR), a transmembrane protein of the inner nuclear membrane. LBR interacts through its nucleoplasmic amino-terminal domain with both heterochromatin and B-type lamins, and is phosphorylated throughout the cell cycle, but on different sites in interphase and mitosis. We report here that: (i) the amino-terminal domain of LBR is specifically cleaved during apoptosis to generate an approximately 20 kDa soluble fragment; (ii) the cleavage of LBR is a late event of apoptosis and occurs subsequent to lamin B cleavage; (iii) the phosphorylation of LBR during apoptosis is similar to that occurring in interphase. As the association of condensed chromatin with the inner nuclear membrane persists until the late stages of apoptosis, we suggest that the chromatin binding protein LBR plays a major role in maintaining this association.

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