Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.11.13 (protein kinase C)
 49,245 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The nucleotide sequence of the full length HSD-3.8 cDNA (accession number AF311312), encoding a human sperm component, was determined to consist of 3818 bp with a reading frame of 2778 bp encoding a deduced polypeptide composed of 926 amino acids. A 0.7 kb fragment containing three immunological epitopes of HSD-3.8 cDNA was prepared and used to construct recombinant expression vectors. The constructs were transformed into E.coli BL-21, and the fusion proteins were expressed, isolated and purified. Using the polyclonal antibodies raised against the purified expressed fusion proteins, positive immunostaining occurred over the surface of the postacrosomal zone of human spermatozoa and of germ cells within the seminiferous epithelium of human testis. Intense staining of large pachytene primary spermatocytes occurred. The capacity of the recombinant protein to reduce fertility as an immunogen in adult female rats was assessed. Immunized animals were infertile or exhibited marked reduction in their fertility. Analysis of the deduced HSD-3.8 polypeptide revealed the presence of a tetratricopeptide repeat (TPR) motif, a P-loop sequence that acts as a binding site for ATP/GTP and phosphorylation sites for PKC, CK2 and cAMP/cGMP-dependent protein kinases. A blot overlay assay with [alpha-(32)P]GTP showed that the polypeptide encoded by the 0.7 kb fragment of HSD-3.8 is a GTP binding protein. It was also shown to possess GTPase activity and to be phosphorylated by PKC in vitro. In conclusion, HSD-3.8 is a GTP binding protein and its activity may be regulated by phosphorylation.
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PMID:Expression and function of the HSD-3.8 gene encoding a testis-specific protein. 1151 87

HSD-3.8 cDNA (accession number AF311312) encodes a human sperm component. A 0.7 kb fragment (HSD-0.7) containing three immunological epitopes of HSD-3.8 cDNA was prepared and expressed in E. coli. Immunization of female rats with the recombinant HSD-0.7 proteins induced infertility. A cDNA fragment encoding the C-terminal 144 amino acids of human G-protein beta l subunit (Gbeta1-C144) was screened by yeast two-hybrid, when HSD-0.7 segment was used as a bait. Recombinant His6-tagged-Gbeta1-C144 protein was expressed in E. coli BL21 and Anti-Gbeta1 serum was raised with purified Gbeta1-C144. HA-tagged HSD-0.7 and FLAG-tagged Gbeta1 plasmids were constructed and co-transfected into human embryonal kidney 293 cells. Two proteins were localized at superimposable sites in the cytoplasm, and they formed a complex when 500 micromol/L GDP existed. Overexpression of HSD-0.7 activated the G-protein-mediated extracellular signal-regulated kinases (ERK1/2); however, the truncated fragments of HSD-0.7, which lacked either TPR domain or P-loop, lost the ability to activate the ERK1/2 pathway. Further study revealed that the activation of ERK1/2 was protein kinase C (PKC) rather than Ras dependent. These results provide evidence that HSD-3.8 present in spermatocytes and sperm may participate in spermatogenesis and fertilization process by activating the PKC-dependent ERK1/2 signal transduction pathway.
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PMID:A sperm component, HSD-3.8 (SPAG1), interacts with G-protein beta 1 subunit and activates extracellular signal-regulated kinases (ERK). 1636 46