Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.11.1 (protein kinase)
 81,284 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

P1 protamines isolated from ejaculated human, stallion, bull, boar and ram spermatozoa and P2 protamines from human and stallion spermatozoa were subjected, after alkaline phosphatase treatment, to in vitro phosphorylation reactions using cAMP-dependent protein kinase (PKA) and protein kinase C (PKC). All P1 protamines were phosphorylated by PKA, whereas P2 protamines were phosphorylated only by PKC. In addition, human, stallion and boar, but not bull and ram, P1 protamines were phosphorylated by PKC. After phosphoamino acid analysis, the protamines showing positive signals for phosphoserine (P-Ser) were subjected to P-Ser conversion reaction and protein sequencing. Only stallion (St1) and human (HP1) P1 protamines contained P-Ser after PKA phosphorylation, located in the middle region of the molecule, i.e., at Ser29 in St1 and Ser28 in HP1. All other phosphorylated P1 protamines contained only P-Thr, which could not be further localized in the sequence with the present methods. After PKC phosphorylation, the internally located Ser residues in human (ser21) and stallion (Ser29) P1 protamines were phosphorylated and, in boar P1 protamine, only Thr43 was slightly phosphorylated. The N-terminally located Ser residues in P1 protamines, which are known to be phosphorylated in vivo, were not phosphorylated by either kinase, indicating that there must still be other types of protamine kinases in sperm cells responsible for their phosphorylation. Within P2 protamines, HP2 was equally well phosphorylated at all Ser residues in addition to some Thr phosphorylation, whereas, in St2, Ser32 was the main target for PKC phosphorylation in vitro. Collectively, PKC is a good candidate for in vivo phosphorylation of P2 protamines and PKA for phosphorylation of some hydroxyamino acid residues in P1 protamines.
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PMID:P2 protamines are phosphorylated in vitro by protein kinase C, whereas P1 protamines prefer cAMP-dependent protein kinase. A comparative study of five mammalian species. 803 90

Human cytomegalovirus phosphoprotein pp65 is targeted to the cell nucleus immediately after infection. Deletion and point mutation analysis of the pp65 gene expressed in insect cells showed that two hydrophilic regions (HP1 and HP2) within the pp65 C-terminal 40% each harboured an independent nuclear localization signal (NLS); strong association to the nuclear stroma also requires the N-terminal domain. Either region, when fused to chloramphenicol acetyltransferase, localized the reporter protein to the nucleus in insect cells as well as in NIH 3T3 cells and human lung fibroblasts. In addition, HP1 was found to be the target of pp65 Ser/Thr phosphorylation in insect cells and a prokaryotically expressed HP1 was actively phosphorylated in vitro by casein kinase II, for which two site clusters map in HP1. These findings indicate that pp65 includes two NLSs, one of which has the potential to be modulated by phosphorylation.
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PMID:Human cytomegalovirus pp65 lower matrix phosphoprotein harbours two transplantable nuclear localization signals. 868

Phosphophoryns (PP), the major noncollagenous proteins (NCPs) in dentin, are believed to play a crucial role in mineral nucleation and hydroxyapatite growth during dentin mineralization. Previously we identified two mature rat PP transcripts, one coding for a 240 amino acid protein (designated as PP(240)) (H.H. Ritchie, L.-H. Wang, J. Biol. Chem. 271 (1996) 21695-21698), and another coding for a 171 amino acid protein (PP(171)) (H. Ritchie, L. Wang, Biochim. Biophys. Acta 1493 (2000) 27-32). We now have identified a third novel dentin sialoprotein (DSP)-PP cDNA transcript that encodes a 523 amino acid protein (PP(523)) with typical PP characteristics including DSS and DS motifs suitable as potential casein kinase I and II phosphorylation sites. Based on amino acid composition, the PP(523) protein product is identical to native rat HP2. We also show that the PP(523) sequence is identical to the corresponding genomic DNA sequence. Taken together, the existence of multiple DSP-PP transcripts, each significantly different from the other in net negative charge, suggests that dentin mineralization processes may be under fine-tune control by these PP protein isoforms.
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PMID:A novel rat 523 amino acid phosphophoryn: nucleotide sequence and genomic organization. 1156 57