scholarly journals The gene for the human tMDC I sperm surface protein is non-functional: implications for its proposed role in mammalian sperm–egg recognition

1998 ◽  
Vol 334 (1) ◽  
pp. 171-176 ◽  
Author(s):  
Jan FRAYNE ◽  
Len HALL
Keyword(s):  
Plasma Membrane ◽  
Macaca Fascicularis ◽  
Surface Protein ◽  
Human Testis ◽  
Egg Recognition ◽  
Integrin Receptor ◽  
Western Blots ◽  
Sperm Surface ◽  
Mammalian Sperm ◽  
Functional Implications

The sperm surface antigen tMDC I (also known as cyritestin) has been proposed to play a role in sperm–egg binding in the mouse via an interaction between its disintegrin-like domain and an integrin receptor on the oolemma plasma membrane. Here we report the cloning and sequence of human tMDC I transcripts and show that they are non-functional, owing to the presence of a variety of deletions, insertions and in-frame termination codons. The absence of a tMDC I protein is further supported by the lack of immunoreactivity on Western blots of human testis and sperm extracts probed with macaque (Macaca fascicularis) and human anti-tMDC I antisera.

scholarly journals Transcripts encoding the sperm surface protein tMDC II are non-functional in the human

1999 ◽  
Vol 341 (3) ◽  
pp. 771-775 ◽  
Author(s):  
Jan FRAYNE ◽  
Elizabeth A. C. DIMSEY ◽  
Jenny A. JURY ◽  
Len HALL
Keyword(s):  
Plasma Membrane ◽  
Macaca Fascicularis ◽  
Surface Protein ◽  
Polyclonal Antiserum ◽  
Human Testis ◽  
Domain Family ◽  
Western Blots ◽  
Rich Domain ◽  
Proposed Model ◽  
Cysteine Rich Domain

Five members of the MDC (metalloproteinase-like,disintegrin-like cysteine-rich domain) family of proteins (fertilin α, fertilin β, tMDC I, tMDC II and tMDC III) are expressed on the surface of macaque (Macaca fascicularis) sperm, where they have been proposed to play a role in sperm-egg binding via an interaction between their disintegrin-like domain and one or more integrins on the egg plasma membrane. Of these, two (fertilin α and tMDC I) have recently been shown to be non-functional in the human. Here we report the existence of multiple isoforms of human tMDC II transcripts in the human, all of which are also non-functional owing to the presence of deletions and in-frame termination codons, when compared with the macaque orthologue, a finding which is further supported by the lack of immunoreactivity on Western blots of human testis and sperm extracts probed with a macaque anti-tMDC II polyclonal antiserum. These results are discussed in the context of our proposed model for multiple proteins implicated in sperm-egg interactions.

scholarly journals Identification and characterization of the 2D6 and Mr 23000 antigens on the plasma membrane of rat spermatozoa

1987 ◽  
Vol 241 (2) ◽  
pp. 353-360 ◽  
Author(s):  
R Jones ◽  
C R Brown
Keyword(s):  
Plasma Membrane ◽  
Antigenic Determinant ◽  
Egg Recognition ◽  
Western Blots ◽  
One Dimensional ◽  
Antigen Present ◽  
Membrane Bound ◽  
Species Specific ◽  
Identification And Characterization

Previous investigations [Jones, Brown, von Glos & Gaunt (1985) Exp. Cell Res. 156, 31-44] have demonstrated the appearance of a new antigenic determinant (recognized by monoclonal antibody 2D6) on the plasma membrane of rat spermatozoa during post-testicular maturation in the epididymis. Identification of the 2D6 antigen on Western blots from one-dimensional SDS/polyacrylamide gels revealed that it co-migrated with a membrane protein (designated Mr 23,000 antigen) present on testicular and immature germ cells, suggesting that one antigen might be a modified version of the other. In the present work, however, we demonstrate that, although they have similar Mr and are present in soluble and membrane-bound forms, the 2D6 and Mr 23,000 antigens are biochemically and immunologically distinct molecules. The properties of the antigens are described and compared. The Mr 23,000 antigen is present on both testicular and cauda epididymidal spermatozoa, has a pI of 6.1, contains no detectable carbohydrate, is not tissue-specific and is degraded by V8 protease. By contrast, the 2D6 antigen is glycosylated, has a broad pI from 4.5 to 6.1, is tissue- and species-specific and is resistant to digestion with V8 protease. Its role in sperm-egg recognition is discussed.

scholarly journals Sperm-egg recognition in the mouse: characterization of sp56, a sperm protein having specific affinity for ZP3.

1994 ◽  
Vol 125 (4) ◽  
pp. 867-878 ◽  
Author(s):  
A Cheng ◽  
T Le ◽  
M Palacios ◽  
L H Bookbinder ◽  
P M Wassarman ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Disulfide Bonds ◽  
Surface Protein ◽  
Exchange Chromatography ◽  
Sperm Head ◽  
Size Exclusion ◽  
Egg Recognition ◽  
Sperm Protein ◽  
Mouse Sperm ◽  
Specific Affinity

Recognition between mammalian gametes occurs when the plasma membrane of the sperm head binds to the zona pellucida (ZP), an extracellular coat surrounding eggs. ZP3, one of three glycoproteins in the ZP, is the egg protein recognized by sperm. A mouse sperm surface protein, sp56 (M(r) = 56,000), has been identified on the basis of its specific affinity for ZP3 (Bleil, J. D., and P. M. Wassarman. 1990. Proc. Natl. Acad. Sci. USA. 87:5563-5567). Studies presented here were designed to characterize mouse sperm sp56 and to further test whether or not this protein specifically recognizes ZP3. sp56 was purified by both ZP3 affinity chromatography and by ion exchange chromatography followed by size-exclusion chromatography. The purified native protein eluted from size-exclusion columns as a homomultimer (M(r) approximately 110,000). Each monomer of the protein contains intramolecular disulfide bonds, consistent with its extracellular location. Immunohistochemical and immunoblotting studies, using monoclonal antibodies, demonstrated that sp56 is a peripheral membrane protein located on the outer surface of the sperm head plasma membrane, precisely where sperm bind ZP3. Results of crosslinking experiments demonstrated that the ZP3 oligosaccharide recognized by sperm has specific affinity for sp56. Collectively, these results suggest that sp56 may be the sperm protein responsible for sperm-egg recognition in the mouse.

scholarly journals A Role for the Disintegrin Domain of Cyritestin, a Sperm Surface Protein Belonging to the ADAM Family, in Mouse Sperm–Egg Plasma Membrane Adhesion and Fusion

1997 ◽  
Vol 137 (1) ◽  
pp. 105-112 ◽  
Author(s):  
Ruiyong Yuan ◽  
Paul Primakoff ◽  
Diana G. Myles
Keyword(s):  
Plasma Membrane ◽  
Membrane Fusion ◽  
Active Site ◽  
Surface Protein ◽  
Equatorial Region ◽  
Cdna Clones ◽  
Sperm Surface ◽  
Disintegrin Domain ◽  
Adam Family ◽  
Membrane Adhesion

Sperm–egg plasma membrane fusion is preceded by sperm adhesion to the egg plasma membrane. Cell–cell adhesion frequently involves multiple adhesion molecules on the adhering cells. One sperm surface protein with a role in sperm–egg plasma membrane adhesion is fertilin, a transmembrane heterodimer (α and β subunits). Fertilin α and β are the first identified members of a new family of membrane proteins that each has the following domains: pro-, metalloprotease, disintegrin, cysteine-rich, EGF-like, transmembrane, and cytoplasmic domain. This protein family has been named ADAM because all members contain a disintegrin and metalloprotease domain. Previous studies indicate that the disintegrin domain of fertilin β functions in sperm–egg adhesion leading to fusion. Full length cDNA clones have been isolated for five ADAMs expressed in mouse testis: fertilin α, fertilin β, cyritestin, ADAM 4, and ADAM 5. The presence of the disintegrin domain, a known integrin ligand, suggests that like fertilin β, other testis ADAMs could be involved in sperm adhesion to the egg membrane. We tested peptide mimetics from the predicted binding sites in the disintegrin domains of the five testis-expressed ADAMs in a sperm–egg plasma membrane adhesion and fusion assay. The active site peptide from cyritestin strongly inhibited (80–90%) sperm adhesion and fusion and was a more potent inhibitor than the fertilin β active site peptide. Antibodies generated against the active site region of either cyritestin or fertilin β also strongly inhibited (80–90%) both sperm–egg adhesion and fusion. Characterization of these two ADAM family members showed that they are both processed during sperm maturation and present on mature sperm. Indirect immunofluorescence on live, acrosome-reacted sperm using antibodies against either cyritestin or fertilin β showed staining of the equatorial region, a region of the sperm membrane that participates in the early steps of membrane fusion. Collectively, these data indicate that a second ADAM family member, cyritestin, functions with fertilin β in sperm–egg plasma membrane adhesion leading to fusion.

Abstract 626: Interaction Between The Ang-(1-7) Receptor Mas And The Bradykinin B2 Receptor: Functional Implications

Hypertension ◽  
2014 ◽  
Vol 64 (suppl_1) ◽  
Author(s):  
Bruno Cerrato ◽  
Oscar Carretero ◽  
Hernán Grecco ◽  
Mariela M Gironacci
Keyword(s):  
Plasma Membrane ◽  
Binding Assays ◽  
Transfected Cells ◽  
Oligomer Formation ◽  
Early Endosomes ◽  
Functional Implications ◽  
Functional Consequences ◽  
Ligand Stimulation ◽  
G Protein Coupled ◽  
Fluorescence Energy

G protein-coupled receptors (R) exist as homo- or hetero-oligomers, which is essential for receptor function. Since BK actions were blocked by a Mas R antagonist or that Ang-(1-7) responses disappeared when the BK receptor B2 was blocked, we hypothesized that Mas and B2 Rs on the plasma membrane may interact through hetero-oligomer formation. Our aim was to investigate the existence of heteromerization between Mas and B2 Rs by the fluorescence energy transfer (FRET) technique and the functional consequences of this oligomer formation. HEK293T cells were transfected with the coding sequence for Mas R fused to YFP and B2 R fused to CFP. After 48 h cells were incubated in the absence and presence of 1 μM Ang-(1-7) or BK during 15 min and interaction between Mas and B2 R was evaluated by FRET. Functional consequences of this interaction were determined by ligand binding assays. A positive FRET was observed in cells cotransfected with MasR-YFP and B2R-CFP, suggesting that both Mas and B2 Rs interact by a hetero-oligomer formation in a constitutive manner. This hetero-oligomer was not altered by the agonist because FRET was not modified when the cells were stimulated with BK or Ang-(1-7). Ang-(1-7) or BK induced internalization of this hetero-oligomer into early endosomes since MasR-YFP or B2R-CFP colocalized with Rab-5, an early endosome marker, after ligand stimulation. When MasR-YFP plus B2R-CFP transfected cells were stimulated with Ang-(1-7) there was a decrease of 82±6% in Mas R and 58±4% in B2 R present in the plasma membrane. Conversely, when MasR-YFP plus B2R-CFP transfected cells were stimulated with BK there was a decrease of 91±4% in B2 R and 53±3% in Mas R in the plasma membrane. This result clearly demonstrates that in co-expressing cells of both receptors the selective stimulation of one of the GPCRs promotes co-internalization of both receptors. We conclude that Mas and B2 Rs constitutively interact through an hetero-oligomer formation at the plasma membrane which may explain the cross-talk between Ang-(1-7) and BK. This hetero-oligomer is internalized upon stimulation with either Ang-(1-7) or BK, leading to a decrease in the number of Rs present in the membrane.

Spreading of a sperm surface antigen within the plasma membrane of the egg after fertilization in the rat

Development ◽  
1983 ◽  
Vol 75 (1) ◽  
pp. 259-270
Author(s):  
Stephen J. Gaunt
Keyword(s):  
Monoclonal Antibody ◽  
Plasma Membrane ◽  
Guinea Pig ◽  
Surface Antigen ◽  
Plasma Membranes ◽  
Entire Surface ◽  
Sperm Tail ◽  
Sperm Surface ◽  
Sperm Antigens

The rat sperm surface antigen 2D6, located over the entire surface of the spermatozoon, is shown by use of a monoclonal antibody in indirect immunofluorescence experiments to spread laterally over the surface of the egg after fusion of sperm and egg plasma membranes at fertilization. Freshly fertilized eggs, obtained from superovulated rats 14h after hCG injection, showed the 2D6 antigen to have spread in a gradient over a discrete fan-shaped area of the egg surface anterior to the protruding sperm tail. Eggs at a later stage of sperm incorporation, obtained 20 h after hCG injection, snowed that the spread of antigen had extended to cover most or all of their surfaces. By 40 h after hCG injection, the approximate time that fertilized eggs cleaved to form 2-cell embryos, most of the 2D6 antigen had been lost from the cell surface. Fertilized eggs, but not unfertilized eggs or 2-cell embryos, were lysed by 2D6 monoclonal antibody in the presence of guinea pig complement. A model for sperm-egg fusion is presented to account for the observed pattern of spreading shown by the 2D6 antigen. The possible role of sperm antigens on the egg surface is discussed.

scholarly journals Biochemical analysis of connexin43 intracellular transport, phosphorylation, and assembly into gap junctional plaques.

1991 ◽  
Vol 115 (5) ◽  
pp. 1357-1374 ◽  
Author(s):  
L S Musil ◽  
D A Goodenough
Keyword(s):  
Plasma Membrane ◽  
Cell Surface ◽  
Gap Junction ◽  
Intracellular Transport ◽  
Surface Protein ◽  
Immunohistochemical Localization ◽  
Junctional Communication ◽  
Junction Protein ◽  
Gap Junctional ◽  
Triton X

We previously demonstrated that the gap junction protein connexin43 is translated as a 42-kD protein (connexin43-NP) that is efficiently phosphorylated to a 46,000-Mr species (connexin43-P2) in gap junctional communication-competent, but not in communication-deficient, cells. In this study, we used a combination of metabolic radiolabeling and immunoprecipitation to investigate the assembly of connexin43 into gap junctions and the relationship of this event to phosphorylation of connexin43. Examination of the detergent solubility of connexin43 in communication-competent NRK cells revealed that processing of connexin43 to the P2 form was accompanied by acquisition of resistance to solubilization in 1% Triton X-100. Immunohistochemical localization of connexin43 in Triton-extracted NRK cells demonstrated that connexin43-P2 (Triton-insoluble) was concentrated in gap junctional plaques, whereas connexin43-NP (Triton-soluble) was predominantly intracellular. Using either a 20 degrees C intracellular transport block or cell-surface protein biotinylation, we determined that connexin43 was transported to the plasma membrane in the Triton-soluble connexin43-NP form. Cell-surface biotinylated connexin43-NP was processed to Triton-insoluble connexin43-P2 at 37 degrees C. Connexin43-NP was also transported to the plasma membrane in communication defective, gap junction-deficient S180 and L929 cells but was not processed to Triton-insoluble connexin43-P2. Taken together, these results demonstrate that gap junction assembly is regulated after arrival of connexin43 at the plasma membrane and is temporally associated with acquisition of insolubility in Triton X-100 and phosphorylation to the connexin43-P2 form.

scholarly journals Localization of Na+,K+-ATPase alpha-subunit to the sinusoidal and lateral but not canalicular membranes of rat hepatocytes.

1987 ◽  
Vol 104 (5) ◽  
pp. 1239-1248 ◽  
Author(s):  
E S Sztul ◽  
D Biemesderfer ◽  
M J Caplan ◽  
M Kashgarian ◽  
J L Boyer
Keyword(s):  
Monoclonal Antibody ◽  
Plasma Membrane ◽  
Horseradish Peroxidase ◽  
Rat Liver ◽  
Plasma Membranes ◽  
Alpha Subunit ◽  
Gamma Glutamyl Transferase ◽  
Surface Distribution ◽  
Western Blots ◽  
Glutamyl Transferase

Controversy has recently developed over the surface distribution of Na+,K+-ATPase in hepatic parenchymal cells. We have reexamined this issue using several independent techniques. A monoclonal antibody specific for the endodomain of alpha-subunit was used to examine Na+,K+-ATPase distribution at the light and electron microscope levels. When cryostat sections of rat liver were incubated with the monoclonal antibody, followed by either rhodamine or horseradish peroxidase-conjugated goat anti-mouse secondary, fluorescent staining or horseradish peroxidase reaction product was observed at the basolateral surfaces of hepatocytes from the space of Disse to the tight junctions bordering bile canaliculi. No labeling of the canalicular plasma membrane was detected. In contrast, when hepatocytes were dissociated by collagenase digestion, Na+,K+-ATPase alpha-subunit was localized to the entire plasma membrane. Na+,K+-ATPase was quantitated in isolated rat liver plasma membrane fractions by Western blots using a polyclonal antibody against Na+,K+-ATPase alpha-subunit. Plasma membranes from the basolateral domain of hepatocytes possessed essentially all of the cell's estimated Na+,K+-ATPase catalytic activity and contained a 96-kD alpha-subunit band. Canalicular plasma membrane fractions, defined by their enrichment in alkaline phosphatase, 5' nucleotidase, gamma-glutamyl transferase, and leucine aminopeptidase had no detectable Na+,K+-ATPase activity and no alpha-subunit band could be detected in Western blots of these fractions. We conclude that Na+,K+-ATPase is limited to the sinusoidal and lateral domains of hepatocyte plasma membrane in intact liver. This basolateral distribution is consistent with its topology in other ion-transporting epithelia.

Abstract 274: Spatiotemporal Regulation of β Adrenergic Signaling In Heart failure

2014 ◽  
Vol 115 (suppl_1) ◽  
Author(s):  
Yang K Xiang ◽  
Federica Barbagallo ◽  
Bing Xu ◽  
Qin Fu
Keyword(s):  
Heart Failure ◽  
Plasma Membrane ◽  
Sarcoplasmic Reticulum ◽  
Cardiac Myocytes ◽  
Cardiac Disease ◽  
Spatiotemporal Regulation ◽  
Disease Therapy ◽  
Functional Implications ◽  
Underlying Mechanisms

Our long-term goal is to understand mechanisms that govern spatiotemporal regulation of cAMP/PKA signaling in cardiac myocytes under physiological and pathophysiological conditions, and their implication in cardiac disease therapy. Here we use a series of biosensors to measure cAMP/PKA activity under βAR subtype regulation. In failing cardiac myocytes, the cAMP and PKA activity are shifted from the plasma membrane to the intracellular sarcoplasmic reticulum and the myofilaments. Meanwhile, β2AR displays an increased role in signaling to the myofilaments in failing myocytes when compared to the control myocytes. Moreover, we show that an increased βAR association with phosphodiesterases promotes the alteration in spatiotemporal propagation of cAMP/PKA signaling in failing myocytes. These observations and the underlying mechanisms and functional implications will be discussed.

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