Necroptosis is one of the regulated cell death, which involves receptor interacting protein kinase (RIPK) 1/RIPK3/mixed lineage kinase domain like protein (MLKL) signaling pathway. Among them, MLKL is the final execution of necroptosis. The formation of RIPK1/RIPK3/MLKL necrosome induces the phosphorylated MLKL, and the activated MLKL penetrates into the membrane bilayer to form membrane pores, which damages the integrity of the membrane and leads to cell death. In addition to participating in necroptosis, MLKL is also closely related to other cell death, such as NETosis, pyroptosis, and autophagy. Therefore, MLKL is involved in the pathological processes of various diseases related to abnormal cell death pathways (such as cardiovascular diseases, neurodegenerative diseases and cancer), and may be a therapeutic target of multiple diseases. Understanding the role of MLKL in different cell death can lay a foundation for seeking various MLKL-related disease targets, and also guide the development and application of MLKL inhibitors.
Protein Kinases/metabolism* ; Necroptosis/physiology* ; Receptor-Interacting Protein Serine-Threonine Kinases ; Signal Transduction ; Pyroptosis ; Apoptosis

Adiponectin, derived mainly from white adipose tissue, regulates glucose and fatty acid metabolism and has anti-inflammatory and anti-atherosclerotic properties. The decrease in plasma adiponectin concentration contributes to the development of metabolic and cardiovascular diseases. AMP-activated protein kinase (AMPK) is a serine/threonine kinase which plays an important role in regulating many cellular processes, particularly pathways involved in cellular energy status. AMPK is now recognized as a fuel gauge in mammalian cells. Adiponectin activates AMPK phosphorylation and then promotes ATP-generating pathways in heart, including glucose transport, glycolysis, and fatty acid oxidation. The recent evidence has shown that AMPK activation has an important role in the vasculature where it may exert anti-atherosclerotic effects. Phosphorylation of AMPK induced by adiponectin inhibits protein synthesis, and may be an adaptive response to pathological cardiac hypertrophy. AMPK also has a cardioprotective role against myocardial injury and apoptosis in the ischemic heart. This review will discuss the role of AMPK in adiponectin-mediated protective properties of cardiovascular diseases.
AMP-Activated Protein Kinases ; metabolism ; Adiponectin ; physiology ; Animals ; Cardiomegaly ; Cardiovascular Diseases ; physiopathology ; Energy Metabolism ; Glucose ; Heart ; Humans ; Multienzyme Complexes ; Phosphorylation ; Protein-Serine-Threonine Kinases

While several organs in mammals retain partial regenerative capability following tissue damage, the underlying mechanisms remain unclear. Recently, the Hippo signaling pathway, better known for its function in organ size control, has been shown to play a pivotal role in regulating tissue homeostasis and regeneration. Upon tissue injury, the activity of YAP, the major effector of the Hippo pathway, is transiently induced, which in turn promotes expansion of tissue-resident progenitors and facilitates tissue regeneration. In this review, with a general focus on the Hippo pathway, we will discuss its major components, functions in stem cell biology, involvement in tissue regeneration in different organs, and potential strategies for developing Hippo pathway-targeted regenerative medicines.
Adaptor Proteins, Signal Transducing ; metabolism ; Animals ; Homeostasis ; physiology ; Humans ; Phosphoproteins ; metabolism ; Protein-Serine-Threonine Kinases ; metabolism ; Regeneration ; physiology ; Signal Transduction ; physiology

Cell cycle plays a crucial role in cell development. Cell cycle progression is mainly regulated by cyclin dependent kinase (CDK), cyclin and endogenous CDK inhibitor (CKI). Among these, CDK is the main cell cycle regulator, binding to cyclin to form the cyclin-CDK complex, which phosphorylates hundreds of substrates and regulates interphase and mitotic progression. Abnormal activity of various cell cycle proteins can cause uncontrolled proliferation of cancer cells, which leads to cancer development. Therefore, understanding the changes in CDK activity, cyclin-CDK assembly and the role of CDK inhibitors will help to understand the underlying regulatory processes in cell cycle progression, as well as provide a basis for the treatment of cancer and disease and the development of CDK inhibitor-based therapeutic agents. This review focuses on the key events of CDK activation or inactivation, and summarizes the regulatory processes of cyclin-CDK at specific times and locations, as well as the progress of research on relevant CDK inhibitor therapeutics in cancer and disease. The review concludes with a brief description of the current challenges of the cell cycle process, with the aim to provide scientific references and new ideas for further research on cell cycle process.
Cyclin-Dependent Kinases/metabolism* ; Cyclins/metabolism* ; Protein Serine-Threonine Kinases ; Cell Cycle Proteins/metabolism* ; Cell Cycle/physiology* ; Cyclin-Dependent Kinase 2

The recent development of a prosaposin -/- mouse model has allowed the investigation of the role of prosaposin in the development of the male reproductive organs. A morphometric analysis of the male reproductive system of 37 days old mice revealed that prosaposin ablation produced a 30 % reduction in size and weight of the testes, 37 % of the epididymis, 75 % of the seminal vesicles and 60 % of the prostate glands. Light microscopy (LM) showed that smaller testis size from homozygous mutant mice was associated with reduced spermiogenesis. Both, dorsal and ventral lobules of the prostate glands were underdeveloped in the homozygous mutant. LM analysis also showed that prostatic alveoli were considerably smaller and lined by shorter epithelial cells in the homozygous mutant. Smaller tubular diameter and shorter undifferentiated epithelial cells were also observed in seminal vesicles and epididymis. In the efferent ducts of the homozygous mutant mice, the epithelium was composed exclusively of ciliated cells in contrast to the heterozygotes, which showed the presence of nonciliated cells. Radioimmunoassays demonstrated that testosterone levels were normal or higher in mice with the inactivated prosaposin gene. Immunostaining of prostate sections with an anti-androgen receptor antibody showed that the epithelial cells lining the alveoli express androgen receptor in both the heterozygous and homozygous tissue. Similarly, sections immunostained with antibodies to the phosphorylated MAPKs and Akts strongly reacted with tall prostatic secretory cells in prostate from heterozygous mouse. On the other hand, the epithelial cells in the homozygous prostate remained unstained or weakly stained. These findings demonstrate that inactivation of the prosaposin gene affected the development of the prostate gland and some components of the MAPK pathway.
Animals ; Glycoproteins ; metabolism ; Humans ; MAP Kinase Signaling System ; physiology ; Male ; Prostate ; growth & development ; metabolism ; Protein-Serine-Threonine Kinases ; Proto-Oncogene Proteins ; metabolism ; Proto-Oncogene Proteins c-akt ; Saposins

BubR1 gene is a homologue of the mitotic checkpoint gene Mad3 in budding yeast which is highly conserved in mammalian. BubR1 protein is a key component mediating spindle assembly checkpoint activation. BubR1 safeguards accurate chromosome segregation during cell division by monitoring kinetochore-microtubule attachments and kinetochore tension. There is a dose-dependent effect between the level of BubR1 expression and the function of spindle assembly checkpoint. BubR1-deficient would lead to mitotic progression with compromised spindle assembly checkpoint because cells become progressively aneuploid. Recently, it has been reported that BubR1 also plays important roles in meiotic, DNA damage response, cancer, infertility, and early aging. This review briefly summarizes the current progresses in studies of BubR1 function.
Cell Cycle Proteins ; genetics ; metabolism ; physiology ; Chromosome Segregation ; genetics ; physiology ; Kinetochores ; metabolism ; physiology ; Mitosis ; genetics ; physiology ; Protein-Serine-Threonine Kinases ; genetics ; metabolism ; physiology ; Saccharomycetales ; genetics ; physiology ; Spindle Apparatus ; genetics ; metabolism ; physiology

OBJECTIVE: To establish an arterial remodeling model of rats and to investigate the expression and role of Hippo signaling pathway in this model. METHODS: In the model group (n=40), the left common carotid artery was removed through the median incision of the neck. The 6-0 non-absorbable line was used to ligate the carotid artery near the proximal end as far as possible, completely blocking the blood flow. The common carotid artery of rats in control group (n=20) was not ligated using the operative line. After 14 days, the animals were sacrificed and the common carotid arteries were separated through the original surgical pathway and the arteries from the ligature to the distal end were collected. Arterial morphology and fibrosis were observed by HE and MASSON staining. Immunohistochemical staining was used to detect the expressions of anti-α smooth muscle actin (α-MSA) and proliferating cell nuclear antigen (PCNA) in the carotid artery. Western blot was used to detect the expressions of yes associated protein (YAP), transcriptional coactivator with PDZ-binding motif (TAZ), TEAD1, Bcl-2-like protein 4 (Bax), and B-cell lymphoma-2 (Bcl-2). RESULTS: Compared with the control group, the HE staining showed that the vascular remodeling was obvious, the ratio of the neointima/middle membrane was increased significantly, and the MASSON staining indicated that the fibrosis was significantly increased in model group. The immunohistochemical staining suggested that the expressions of α-SMA and PCNA were increased significantly; Western blot suggested that the expressions of YAP, TAZ, TEAD1, and Bcl-2 were increased in carotid artery of the model group. While the expression of Bax and the ratio of Bax/Bcl-2 were decreased. CONCLUSION A rat model of arterial remodeling mediated by carotid artery ligation was established successfully in this study. Hippo signaling pathway was proved to be activated in the arterial remodeling model induced by carotid artery ligation in rats, and might regulate the change of Bax/Bcl-2 ratio related to proliferation and apoptosis, and subsequently involved in the proliferation of smooth muscle cells to promote vascular remodeling.
Animals ; Carotid Arteries ; metabolism ; Carotid Artery, Common ; Cell Proliferation ; Myocytes, Smooth Muscle ; Protein-Serine-Threonine Kinases ; metabolism ; Rats ; Signal Transduction ; Vascular Remodeling ; physiology

OBJECTIVETo investigate the MEK and ERK expression and their relationship with clinicopathological parameters in human breast carcinoma, and the effect of preoperative chemotherapy on MEK and ERK protein expression.

METHODSSamples were obtained from 56 patients with breast carcinoma and 8 patients with benign tumors. Sixteen of the 56 patients received preoperative chemotherapy. Western blot and immunohistochemistry were used to measure the expression of MEK1, MEK2 and ERK1, ERK2 protein.

RESULTSMEK2 and ERK1, ERK2 protein levels were increased in breast carcinoma tissue compared with those in adjacent normal tissues (t = 7.244, 5.959, 3.735, P < 0.01) and benign tumors (t = 2.206, P < 0.05). The levels of MEK1 were decreased. The expression of MEK2 protein in ER negative patients was higher than that in ER positive ones. MEK2 protein levels were lower in patients who received preoperative chemotherapy than in those who did not.

CONCLUSIONOverexpression of MEK-ERK may play an important role in the development of human breast carcinoma. MEK and ERK protein expressions are inhibited by preoperative chemotherapy.

Adult ; Aged ; Blotting, Western ; Breast Neoplasms ; diagnosis ; enzymology ; metabolism ; Female ; Humans ; Immunohistochemistry ; MAP Kinase Kinase 1 ; MAP Kinase Kinase 2 ; MAP Kinase Signaling System ; physiology ; Middle Aged ; Mitogen-Activated Protein Kinase 1 ; metabolism ; Mitogen-Activated Protein Kinase 3 ; Mitogen-Activated Protein Kinase Kinases ; metabolism ; Mitogen-Activated Protein Kinases ; metabolism ; Prognosis ; Protein Kinases ; metabolism ; Protein-Serine-Threonine Kinases ; metabolism ; Protein-Tyrosine Kinases ; metabolism

OBJECTIVETo evaluate the effect of heat shock protein 90 (HSP90) on hepatitis B virus (HBV) replication in hepatocytes and to investigate the related molecular mechanism.

METHODSA eukaryotic plasmid expressing human HSP90 was constructed (designated as HA-HSP90). HepG2 cells were co-transfected with HA-HSP90 and the HBV replicative plasmid HBV1.3. Expression of the exogenous HSP90 was assessed by Western blotting. Expression of the HBV surface antigen (HBsAg) was determined by enzyme-linked immunosorbent assay, and HBV replicative intermediates were detected by Southern blotting. Small interfering (si)RNAs were designed against HSP90 and TBK1 and transfected into the HepG2 cells to further assess the effects of HSP90 and its underlying mechanism. HSP90-mediated effects on the expression of interleukins IL-1b and IL-6 and the interferon response gene IFIT1 were assessed by quantitating mRNA levels with real time RT-PCR.

RESULTSThe HA-HSP90 plasmid successfully expressed exogenous HSP90 protein in HepG2 cells. The exogenous HSP90 was able to inhibit HBV replication and HBsAg expression. IFIT1 expression was up-regulated after HA-HSP90 transfection, but neither IL-1b nor IL-6 were affected. The siRNA-mediated TBK1 down-regulation had no effect on the HSP90-inhibited HBV replication.

CONCLUSIONHSP90 can inhibit HBV replication and TBK1 is not involved in this process.

HSP90 Heat-Shock Proteins ; genetics ; Hep G2 Cells ; Hepatitis B e Antigens ; metabolism ; Hepatitis B virus ; physiology ; Humans ; Protein-Serine-Threonine Kinases ; genetics ; Transfection ; Virus Replication

Studies of epilepsy have mainly focused on the membrane proteins that control neuronal excitability. Recently, attention has been shifting to intracellular proteins and their interactions, signaling cascades and feedback regulation as they relate to epilepsy. The mTOR (mammalian target of rapamycin) signal transduction pathway, especially, has been suggested to play an important role in this regard. These pathways are involved in major physiological processes as well as in numerous pathological conditions. Here, involvement of the mTOR pathway in epilepsy will be reviewed by presenting; an overview of the pathway, a brief description of key signaling molecules, a summary of independent reports and possible implications of abnormalities of those molecules in epilepsy, a discussion of the lack of experimental data, and questions raised for the understanding its epileptogenic mechanism.
Astrocytes/metabolism ; Cell Death ; Epilepsy/diet therapy/drug therapy/*metabolism/virology ; Humans ; Ketogenic Diet ; Protein Binding/physiology ; Protein Kinase Inhibitors/therapeutic use ; Receptors, Cannabinoid/metabolism ; Signal Transduction/*physiology ; Synapses/metabolism ; TOR Serine-Threonine Kinases/antagonists & inhibitors/*metabolism ; Temporal Lobe/metabolism