Hamster Oviductin Regulates Tyrosine Phosphorylation of Sperm Proteins During In Vitro Capacitation1

The recent finding that sheep had long (l-oPRLR) and short (s-oPRLR) prolactin receptors provided new tools to further explore prolactin signaling to target genes. Here we used CHO cells transfected with l-oPRLR or s-oPRLR cDNAs to compare the activation of known key steps of prolactin signaling by the two receptors. We found that prolactin stimulated l-oPRLR tyrosine phosphorylation, although it lacked the last tyrosine residue found in other long prolactin receptors. In addition, l-oPRLR and s-oPRLR both responded to prolactin stimulation by (1) Janus kinase 2 (Jak2) tyrosine phosphorylation, (2) DNA-binding activation of signal transducer and activator of transcription 5 (STAT5), (3) stimulation of transcription from a promoter made of six repeats of STAT5-responsive sequence. However, although it contains STAT5-binding consensus sequences, the ovine beta-lactoglobulin promoter (-4000 to +40) was transactivated by l-oPRLR, but not by s-oPRLR. Taken together, our results indicate that activation of Jak2/STAT5 pathway alone is not sufficient to account for prolactin-induced transcription of this milk protein gene, and that sequences of its promoter, other than STAT5-specific sequences, account for the opposite transcriptional activation capabilities of l-oPRLR and s-oPRLR.

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An Insight into Novel Sperm Cell Proteins as Bio-markers for Male Infertility: A Review

Current Molecular Medicine ◽

10.2174/1566524021666210121142612 ◽

2021 ◽

Vol 21 ◽

Author(s):

Naina Kumar ◽

Namit Kant Singh

Keyword(s):

Male Infertility ◽

Sperm Motility ◽

Zona Pellucida ◽

English Language ◽

Semen Analysis ◽

Meta Analysis ◽

Sperm Dna Damage ◽

Sperm Proteins

: Male infertility is rising now-a-days and accounts for major part of infertility cases worldwide. Novel tests are being developed for better detection and management of male infertility. Though there are many tests available for diagnosing male infertility like acrosome reaction rate, hemizona assay, in vivo or in vitro sperm penetration assay, sperm DNA damage tests, but semen analysis is most commonly used initial test for male infertility. It is usually associated with failure to detect cause in many cases, as seminal composition gets affected by a number of factors and can give false reports. Furthermore, it does not give any information about defects in capacitation, sperm Zona Pellucida interaction and sperm’s ability to fertilize oocytes. This results in failure of detection and delayed management of male infertility. Hence, the present review was conducted to identify various sperm proteins that play significant role in spermatogenesis, sperm motility, sperm-Zona Pellucida interaction and fertilization. These proteins can be used in future as markers of male infertility and will aid in better detection and management of male infertility. Methodology: Search for literature was made from 1970 to 2020 from various databases like PUBMED, SCOPUS, Google Scholar on sperm proteins and their role in male fertility using keywords: “sperm protein as bio-markers”, “novel sperm proteins as markers of infertility”, “Sperm proteins essential for capacitation, sperm motility and oocyte fertilization”. Inclusion criteria: All full-length research articles, systematic reviews, meta-analysis or abstracts on sperm proteins and male infertility published in English language in peer-reviewed journals were considered.

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Involvement of Shc in insulin- and epidermal growth factor-induced activation of p21ras

Molecular and Cellular Biology ◽

10.1128/mcb.14.3.1575-1581.1994 ◽

1994 ◽

Vol 14 (3) ◽

pp. 1575-1581

Author(s):

G J Pronk ◽

A M de Vries-Smits ◽

L Buday ◽

J Downward ◽

J A Maassen ◽

...

Keyword(s):

Growth Factor ◽

Epidermal Growth Factor ◽

Insulin Receptor ◽

Tyrosine Phosphorylation ◽

Egf Receptor ◽

Growth Factor Receptor ◽

Nucleotide Exchange ◽

Similar Time ◽

Epidermal Growth

Shc proteins are phosphorylated on tyrosine residues and associate with growth factor receptor-bound protein 2 (Grb2) upon treatment of cells with epidermal growth factor (EGF) or insulin. We have studied the role of Shc in insulin- and EGF-induced activation of p21ras in NIH 3T3 cells overexpressing human insulin receptors (A14 cells). A14 cells are equally responsive to insulin and EGF with respect to activation of p21ras. Analysis of Shc immunoprecipitates revealed that (i) both insulin and EGF treatment resulted in Shc tyrosine phosphorylation and (ii) Shc antibodies coimmunoprecipitated both Grb2 and mSOS after insulin and EGF treatment. The induction of tyrosine phosphorylation of Shc and the presence of Grb2 and mSOS in Shc immunoprecipitates followed similar time courses, with somewhat higher levels after EGF treatment. In mSOS immunoprecipitates, Shc could be detected as well. Furthermore, Shc immune complexes contained guanine nucleotide exchange activity toward p21ras in vitro. From these results, we conclude that after insulin and EGF treatment, Shc associates with both Grb2 and mSOS and therefore may mediate, at least in part, insulin- and EGF-induced activation of p21ras. In addition, we investigated whether the Grb2-mSOS complex associates with the insulin receptor or with insulin receptor substrate 1 (IRS1). Although we observed association of Grb2 with IRS1, we did not detect complex formation between mSOS and IRS1 in experiments in which the association of mSOS with Shc was readily detectable. Furthermore, whereas EGF treatment resulted in the association of mSOS with the EGF receptor, insulin treatment did not result in the association of mSOS with the insulin receptor. These results indicate that the association of Grb2-nSOS with Shc may be an important event in insulin-induced, mSOS-mediated activation of p21ras.

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Structural and functional modification of pp60c-src associated with polyoma middle tumor antigen from infected or transformed cells

Molecular and Cellular Biology ◽

10.1128/mcb.5.10.2647-2652.1985 ◽

1985 ◽

Vol 5 (10) ◽

pp. 2647-2652

Author(s):

C A Cartwright ◽

M A Hutchinson ◽

W Eckhart

Keyword(s):

Protein Kinase ◽

Tyrosine Phosphorylation ◽

Tumor Antigen ◽

Kinase Activity ◽

Protein Kinase Activity ◽

Amino Terminal ◽

Exogenous Substrate ◽

And Function ◽

Amino Terminal Domain

The polyoma middle tumor antigen (MTAg) associates with the src proto-oncogene product pp60c-src in infected or transformed rodent cells. The tyrosine protein kinase activity of pp60c-src, as measured by in vitro phosphorylation of pp60c-src itself or the exogenous substrate enolase, was increased 10- to 20-fold in cells transformed or infected with transformation-competent polyoma virus compared with controls. pp60c-src associated with MTAg and precipitated with polyoma antitumor serum had a novel site(s) of in vitro tyrosine phosphorylation within its amino-terminal domain. These observations suggest that association of MTAg with pp60c-src alters the accessibility of pp60c-src tyrosine residues for phosphorylation in vitro and increases pp60c-src protein kinase activity. Several transformation-defective mutants of MTAg did not cause amino-terminal tyrosine phosphorylation of pp60c-src in vitro or enhance its protein kinase activity, suggesting that these properties correlate with the transforming ability of MTAg. However, one transformation-defective MTAg mutant, dl1015, did cause amino-terminal tyrosine phosphorylation of pp60c-src in vitro and did enhance its protein kinase activity. This suggests that properties of MTAg, in addition to modifying the structure and function of pp60c-src, may be important for transformation.

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Platelet-derived growth factor (PDGF)-dependent association of phospholipase C-gamma with the PDGF receptor signaling complex

Molecular and Cellular Biology ◽

10.1128/mcb.10.5.2359-2366.1990 ◽

1990 ◽

Vol 10 (5) ◽

pp. 2359-2366

Author(s):

D K Morrison ◽

D R Kaplan ◽

S G Rhee ◽

L T Williams

Keyword(s):

Growth Factor ◽

Tyrosine Phosphorylation ◽

Serine Phosphorylation ◽

Platelet Derived Growth Factor ◽

Pdgf Receptor ◽

Wild Type ◽

Receptor Proteins ◽

Signaling Complex

We investigated the interaction of phospholipase C-gamma (PLC-gamma) with wild-type and mutant forms of the platelet-derived growth factor (PDGF) beta-receptor both in vivo and in vitro. After PDGF treatment of CHO cell lines expressing wild-type or either of two mutant (delta Ki and Y825F) PDGF receptors, PLC-gamma became tyrosine phosphorylated and associated with the receptor proteins. The receptor association and tyrosine phosphorylation of PLC-gamma correlated with the ability of these receptors to mediate ligand-induced phosphatidylinositol turnover. However, both the delta Ki and Y825F mutant receptors were deficient in transmitting mitogenic signals, suggesting that the PDGF-induced tyrosine phosphorylation and receptor association of PLC-gamma are not sufficient to account for the growth-stimulatory activity of PDGF. Wild-type and delta Ki mutant PDGF receptor proteins expressed with recombinant baculovirus vectors also associated in vitro with mammalian PLC-gamma. However, baculovirus-expressed c-fms, v-fms, c-src, and Raf-1 proteins failed to associate with PLC-gamma under similar conditions. Phosphatase treatment of the baculovirus-expressed PDGF receptor greatly decreased its association with PLC-gamma. This requirement for receptor phosphorylation was also observed in vivo, where PLC-gamma could not associate with a mutant PDGF receptor (K602A) defective in autophosphorylation. PLC-gamma also coimmunoprecipitated with two other putative receptor substrates, the serine-threonine kinase Raf-1 and the 85-kilodalton phosphatidylinositol-3' kinase, presumably through its association with the ligand-activated receptor. Furthermore, baculovirus-expressed Raf-1 phosphorylated purified PLC-gamma in vitro at sites which showed increased serine phosphorylation in vivo in response to PDGF. These results suggest that PDGF directly influences PLC activity by inducing the association of PLC-gamma with a receptor signaling complex, resulting in increased tyrosine and serine phosphorylation of PLC-gamma.

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Abstract 12231: PECAM1 is Essential for Flow-mediated Gab1 Tyrosine Phosphorylation and Signaling in vitro and in vivo

Circulation ◽

10.1161/circ.132.suppl_3.12231 ◽

2015 ◽

Vol 132 (suppl_3) ◽

Author(s):

Suowen Xu ◽

Marina Koroleva ◽

Keigi Fujiwara ◽

Zheng Gen Jin

Keyword(s):

Tyrosine Phosphorylation ◽

Wheel Running ◽

Tyrosine Phosphatase ◽

Common Mechanism ◽

Membrane Localization ◽

No Production ◽

Voluntary Wheel Running ◽

Voluntary Wheel

Introduction: Impaired activation of endothelial nitric oxide (NO) synthase (eNOS) and ensued NO production is a common mechanism of various cardiovascular pathologies, including hypertension and atherosclerosis. Specific signaling cascades, generated by vascular endothelial cells (ECs) in response to laminar flow, modulate EC structure and functions, NO production in particular. We have previously shown that flow-stimulated Gab1 (Grb2-associated binder-1) tyrosine phosphorylation mediates eNOS activation. However, the upstream mechanism that regulates Gab1 tyrosine phosphorylation remains unclear. Hypothesis: We hypothesized that platelet endothelial cell adhesion molecule-1 (PECAM1), a key molecule in an endothelial mechanosensing complex, specifically mediates Gab1 tyrosine phosphorylation and its downstream Akt and eNOS activation in ECs upon flow rather than hepatocyte growth factor (HGF) stimulation. Methods: Western blot, en face staining and voluntary wheel running. Results: Small interfering RNA (siRNA) targeting PECAM1 abolished flow- but not HGF-induced Gab1 tyrosine phosphorylation and Akt, eNOS activation as well as Gab1 membrane translocation. Protein-tyrosine phosphatase SHP2, which has been shown to interact with Gab1, was involved in a flow signaling pathway as well as HGF-induced signaling, as SHP2 siRNA diminished the flow- and HGF-induced Gab1 tyrosine phosphorylation, membrane localization and downstream signaling. Pharmacological inhibition of PI3K by LY294002 decreased flow, but not HGF-mediated Gab1 phosphorylation and membrane localization as well as eNOS activation. Finally, we observed that flow-mediated Gab1 and eNOS phosphorylation in vivo induced by voluntary wheel running was reduced in PECAM1 knockout mice. Conclusions: These results demonstrate a specific role of PECAM1 in flow-mediated Gab1 tyrosine phosphorylation and eNOS signaling in ECs

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Tyrosine phosphorylation enhances activity of pneumococcal autolysin LytA

Microbiology ◽

10.1099/mic.0.080747-0 ◽

2014 ◽

Vol 160 (12) ◽

pp. 2745-2754 ◽

Cited By ~ 11

Author(s):

Alistair J. Standish ◽

Jonathan J. Whittall ◽

Renato Morona

Keyword(s):

Tyrosine Phosphorylation ◽

Protein Tyrosine Phosphatase ◽

Capsular Polysaccharide ◽

Regulatory Mechanism ◽

Tyrosine Phosphatase ◽

Phosphorylation Site ◽

Regulatory Proteins ◽

Amidase Activity ◽

The Past

Tyrosine phosphorylation has long been recognized as a crucial post-translational regulatory mechanism in eukaryotes. However, only in the past decade has recognition been given to the crucial importance of bacterial tyrosine phosphorylation as an important regulatory feature of pathogenesis. This study describes the effect of tyrosine phosphorylation on the activity of a major virulence factor of the pneumococcus, the autolysin LytA, and a possible connection to the Streptococcus pneumoniae capsule synthesis regulatory proteins (CpsB, CpsC and CpsD). We show that in vitro pneumococcal tyrosine kinase, CpsD, and the protein tyrosine phosphatase, CpsB, act to phosphorylate and dephosphorylate LytA. Furthermore, this modulates LytA function in vitro with phosphorylated LytA binding more strongly to the choline analogue DEAE. A phospho-mimetic (Y264E) mutation of the LytA phosphorylation site displayed similar phenotypes as well as an enhanced dimerization capacity. Similarly, tyrosine phosphorylation increased LytA amidase activity, as evidenced by a turbidometric amidase activity assay. Similarly, when the phospho-mimetic mutation was introduced in the chromosomal lytA of S. pneumoniae, autolysis occurred earlier and at an enhanced rate. This study thus describes, to our knowledge, the first functional regulatory effect of tyrosine phosphorylation on a non-capsule-related protein in the pneumococcus, and suggests a link between the regulation of LytA-dependent autolysis of the cell and the biosynthesis of capsular polysaccharide.

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Signal transduction mechanisms involved in in vitro ram sperm capacitation

Reproduction ◽

10.1530/rep.1.00770 ◽

2006 ◽

Vol 132 (5) ◽

pp. 721-732 ◽

Cited By ~ 45

Author(s):

Patricia Grasa ◽

José Álvaro Cebrián-Pérez ◽

Teresa Muiño-Blanco

Keyword(s):

Tyrosine Phosphorylation ◽

Calcium Influx ◽

Calcium Entry ◽

Calcium Entry Blocker ◽

Protein Tyrosine Phosphorylation ◽

Sperm Capacitation ◽

Protein Tyrosine ◽

Entry Blocker ◽

Ram Sperm

We validate the chlortetracycline (CTC) technique for the evaluation of capacitation and acrosome reaction-like changes in ram sperm, carrying out a double estimation of the acrosome status after treatment with lysophosphatidylcholine, using fluorescein isocyanate (FITC)-RCA/ethidium homodimer 1 (EthD-1) and CTC/EthD-1. Highly consistent results and a positive correlation between the results of acrosome-reacted sperm evaluated with both techniques were obtained. In this study, we evaluate the effects of ram sperm capacitation of BSA, Ca2+, NaHCO3and cAMP agonists and their influence on the associated protein tyrosine phosphorylation. We found a time-dependent increase in capacitation related to protein tyrosine phosphorylation, either in the absence or the presence of BSA. The addition of an increasing concentration of cholesterol to samples containing BSA did not influence results. The effect of bicarbonate was concentration-dependent, with a significantly lowered value of non-capacitated sperm in the presence 18 and 25 mM. The addition of extracellular calcium did not significantly increase either the proportion of capacitated sperm or the protein tyrosine phosphorylation signalling, although a significantly higher value of acrosome-reacted sperm was found in samples containing 4 mM Ca2+. cAMP agonists increased capacitated sperm and protein tyrosine phosphorylation signalling. The inhibition of protein kinase A by H-89 caused a decrease in sperm capacitation. Addition of a calcium-entry blocker (Verapamil; Sigma) did not influence results, which suggests that the calcium entry blocker was unable to inhibit the calcium influx associated with capacitation in ram sperm. Our findings might benefit our understanding of the biochemical mechanisms involved in mammalian sperm capacitation and ultimately, fertility.

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