• BMB Reports
• /
• v.44 no.9
• /
• pp.584-589
• /
• 2011

The mammalian ste20-like kinase (MST) pathway is important in the regulation of apoptosis and cell cycle and emerges as a novel tumor suppressor pathway. MST-induced phosphorylation of Salvador homolog 1 (SAV1), which is a scaffold protein, has not been evaluated in detail. We performed a mass spectrometric analysis of the SAV1 protein that was co-expressed with MST2. Phosphorylation was detected at Thr-26, Ser-27, Ser-36 and Ser-269. Although single or double mutations had little effects, the mutation of all four residues in SAV1 to Ala (SAV1-4A) had inhibitory effects on the MST pathway. MST2-mediated induction of SAV1-4A protein levels, SAV1-4A interaction with MST2 and the self-dimerization of SAV1-4A were weaker compared to those of wild-type SAV1. SAV1-4A inhibited MST2- and K-RasG12V-induced cell death of MCF7 cells. These results suggest that MST-mediated phosphorylation of four residues within SAV1 may be important in the induction of cell death by the MST pathway.

• Molecules and Cells
• /
• v.25 no.2
• /
• pp.317-321
• /
• 2008

Members of the large family of Asb proteins are ubiquitously expressed in mammalian tissues; however, the roles of individual Asb and their function in the developmental testes have not been reported. In this report, we isolated a murine Asb4 from mouse testis. Northern blot analysis revealed that mAsb-4 was expressed only in testes and produced in a stage-specific manner during spermatogenesis. It was expressed in murine testes beginning in the fourth week after birth and extending into adulthood. Pachytene spermatocytes had the highest level of expression. Interestingly, the human homologue of mAsb-4, ASB-4 (hASB-4) was also expressed in human testis. These results suggest that ASB-4 plays pivotal roles in mammalian testis development and spermatogenesis.

• Proceedings of the Korean Society of Food Hygiene and Safety Conference
• /
• 2001.10a
• /
• pp.243-247
• /
• 2001

• Journal of Microbiology and Biotechnology
• /
• v.9 no.2
• /
• pp.227-229
• /
• 1999

Animal cell culture media are usually supplemented with fetal bovine serum (FBS); however, the use of FBS presents certain problems including high cost. By using an adaptation process and the addition of silkworm hemolymph, the FBS concentration can be reduced without causing a significant decrease in cell growth.

• Biomedical Science Letters
• /
• v.11 no.2
• /
• pp.103-108
• /
• 2005

2-Deoxyribonolactone (dL) arises as a major DNA damage induced by a variety of agents, involving free radical attack and oxidation of C1'-deoxyribose in DNA. We investigated whether dL lesions can be repaired in mammalian cells and the mechanisms underlying the role of DNA polymerase $\beta$ in processing of dL lesions. Pol $\beta$ appeared to be trapped by dL residues, resulting in stable DNA-protein cross-links. However, repair DNA synthesis at site-specific dL sites occurred effectively in cell-free extracts, but predominantly accompanied by long-patch base excision repair (BER) pathway. Reconstitution of long-patch BER demonstrated that FEN1 was capable of removing the displaced flap DNA containing a 5'-dL residue. Cellular repair of dL lesions was largely dependent on the DNA polymerase activity of Pol $\beta$. Our observations reveal repair mechanisms of dL and define how mammalian cells prevent cytotoxic effects of oxidative DNA lesions that may threaten the genetic integrity of DNA.

• 한국생물공학회:학술대회논문집
• /
• 2002.04a
• /
• pp.62-65
• /
• 2002

We have previously shown that the addition of silkworm hemolymph to a culture medium increases the longevity of insect and mammalian cells by inhibiting apoptosis. This indicates that the component which inhibits apoptosis is contained in the silkworm hemolymph, The apoptosis-inhibiting component was isolated from silkwonn hemolymph and characterized in our previous study. A database search using the N-terminal amino acid sequence of this component as a template resulted in a 95% homology with a low molecular weight lipoprotein, the so called ’30K protein' of unknown function. In this study, the 30K protein gene was expressed in mammalian and insect cells to confirm the apoptosis-inhibiting effect. The overexpression of 30K protein in mammalian cell inhibited the staurosporin-induced apoptosis by the prevention of the activation of caspase 3. Using an Autographa californicanuclear polyhedrosis virus (AcNPV) system, the 30K protein was overexpressed also in insect cells. The expression of the 30K protein increased the longevity of baculovirus-infected insect cells by inhibiting apoptosis. These results suggest that the 30K protein is a novel anti-apoptotic protein.

• Microbiology and Biotechnology Letters
• /
• v.40 no.4
• /
• pp.409-413
• /
• 2012

Indolicidin (ID) is a 13-residue Trp-rich antimicrobial peptide (AMP) isolated from bovine neutrophils. In addition to having a high antimicrobial potency, it is also toxic to mammalian cells. To develop novel ID-derived AMPs with shorter lengths and enhanced prokaryotic selectivities (meaning potent antimicrobial activity against bacterial cells without toxicity against mammalian cells) over the parental ID, several ID analogs were designed and synthesized. Finally, 10-residue ID analogs (SI, SI-PA, SI-WF and SI-WL) with much higher prokaryotic selectivity than the parental ID were developed. Our results suggest that the hydrophobic and aromatic amino acids at the central position of the analog SI with the highest prokaryotic selectivity are important for potent antimicrobial activity, but two Pro residues do not affect antimicrobial activity. The order of prokaryotic selectivity for ID and its designed analogs was SI > SI-PA > SI-WF > SI-WL > ID > SI-WA. Taken together, our designed short ID analogs could be developed as therapeutic agents for treating bacterial infections.

• Animal cells and systems
• /
• v.6 no.4
• /
• pp.317-322
• /
• 2002

To improve conventional yeast one-hybrid screening, we have developed an efficient mammalian one-hybrid system that allows rapid isolation of com-plementary DNAs which are able to induce human p14$^{ARF}$. tumor suppressor gene. A 1.5 kb promoter region of p14$^{ARF}$ was fused to EGFP to generate ARF promoter-EGFP reporter vector. This reporter plasmid was stably trans-fected into NIH3T3 cells for generation of reporter cell line. When the reporter cell line was infected with E2F-1 together with excess amounts of empty vector, the cells that received the positive modulator were readily identifiable by green fluorescence using FACS. The GFP-positive cells were cloned directly from the cultured cells and expanded in bulk culture. The genomic DNAs from GFP-positive cells were prepared and the CDNA insert in integrated retroviral genome was recovered by PCR using primers annealing to the retroviral vector sequences flanking the insert-cloning site. This system should be useful for efficient screening of expression CDNA libraries in mammalian cells to identify novel upstream regulators for spe-cific genes by one-hybrid interaction.ion.

• Animal cells and systems
• /
• v.16 no.3
• /
• pp.173-182
• /
• 2012

The p53 protein plays a pivotal role in tumor suppression. The cellular level of p53 is normally kept low by proteasome-mediated degradation, allowing cell cycle progression and cell proliferation. Under stress conditions, such as DNA damage, p53 is stabilized and activated through various post-translational modifications of itself as well as of its regulatory proteins for induction of the downstream genes responsible for cell cycle arrest, DNA repair, and apoptosis. Therefore, the level of p53 should be tightly regulated for normal cell growth and for prevention of the accumulation of mutations in DNA under stress conditions, which otherwise would lead to tumorigenesis. Since the discovery of Mdm2, a critical ubiquitin E3 ligase that destabilizes p53 in mammalian cells, nearly 20 different E3 ligases have been identified and shown to function in the control of stability, nuclear export, translocation to chromatin or nuclear foci, and oligomerization of p53. So far, a large number of excellent reviews have been published on the control of p53 function in various aspects. Therefore, this review will focus only on mammalian ubiquitin E3 ligases that mediate proteasome-dependent degradation of p53.

• Asian-Australasian Journal of Animal Sciences
• /
• v.21 no.3
• /
• pp.456-464
• /
• 2008

Avian and mammalian skeletal muscles exhibit a remarkable ability to adjust to physiological stressors induced by growth, exercise, injury and disease. The process of muscle recovery following injury and myonuclear accretion during growth is attributed to a small population of satellite cells located beneath the basal lamina of the myofiber. Several metabolic factors contribute to the activation of satellite cells in response to stress mediated by illness, injury or aging. This review will describe the regenerative properties of satellite cells, the processes of satellite cell activation and highlight the potential role of satellite cells in skeletal muscle growth, tissue engineering and meat production.