cellular protein

Protein phosphorylation is a key post-translational modification underlying the regulation of many cellular processes. Phosphatases and kinases contribute to the regulation of protein phosphorylation homeostasis in the cell. This reversible regulation of protein phosphorylation is critical for the proper control of a wide range of cellular activities, including cell cycle, proliferation and differentiation, metabolism, cell-cell interactions, etc.

Protein phosphatases have evolved in separate families that are structurally and mechanistically distinct. Based on substrate specificity and functional diversity, protein phosphatases are classified into two superfamilies: Protein serine/threonine phosphatases and Protein tyrosine phosphatases. Ser/Thr phosphatases are metalloenzymes belonging to two major gene families termed PPP (phosphoprotein phosphatase) and PPM (metal-dependent protein phosphatases), whereas protein tyrosine phosphatases (PTPs) belong to distinct classes of enzymes that utilize a phospho-cysteine enzyme intermediate as a part of their catalytic action.

MCE supplies a unique collection of 128 phosphatase inhibitors that mainly targeting protein tyrosine phosphatases (PTPs) and serine/threonine-specific protein phosphatases. MCE Phosphatase Inhibitor Library is a useful tool for phosphatase drug discovery and related research.

Protein ubiquitination is an enzymatic post-translational modification in which an ubiquitin protein is attached to a substrate protein. Ubiquitination involves three main steps: activation, conjugation, and ligation, performed by ubiquitin-activating enzymes (E1s), ubiquitin-conjugating enzymes (E2s), and ubiquitin ligases (E3s), respectively. Ubiquitination affects cellular processes such as apoptosis, cell cycle, DNA damage repair, and membrane transportation, etc. by regulating the degradation of proteins (via the proteasome and lysosome), altering the cellular localization of proteins, affecting proteins activity, and promoting or preventing protein-protein interactions. Deregulation of ubiquitin pathway leads to many diseases such as neurodegeneration, cancer, infection and immunity, etc.

MCE offers a unique collection of 271 small molecule modulators with biological activity used for ubiquitination research. Compounds in this library target the key enzymes in ubiquitin pathway. MCE Ubiquitination Compound Library is a useful tool for the research of ubiquitination regulation and the corresponding diseases.

Endoplasmic reticulum (ER) contributes to the production and folding of approximately one third of cellular proteins, and is thus inextricably linked to the maintenance of cellular homeostasis and the fine balance between health and disease. However, some adverse factors negatively impact ER functions and protein synthesis, resulting in the activation of Endoplasmic reticulum stress (ER stress, ERS) and unfolded protein response (UPR) signaling pathways. The UPR is triggered when ER protein folding capacity is overwhelmed by cellular demand and the UPR initially aims to restore ER homeostasis and normal cellular functions. However, if this fails, then the UPR triggers cell death. Chronic ER stress and defects in UPR signaling are emerging as key contributors to a growing list of human diseases, including diabetes, neurodegeneration and cancer.

MCE Endoplasmic Reticulum Stress Compound Library contains 227 ER stress-related compounds that mainly target PERK, IRE1, ATF6, etc. MCE ER stress library is a useful tool for researching ER stress and related diseases.

A protease (also called a peptidase, proteinase, or proteolytic enzyme) is an enzyme that catalyzes proteolysis, breaking down proteins into smaller polypeptides or single amino acids, and spurring the formation of new protein products. Proteases play important roles in regulating multiple biological processes in all living organisms, such as regulating the fate, localization, and activity of many proteins, modulating protein-protein interactions, creating new bioactive molecules, contributing to the processing of cellular information, and generating, transducing, and amplifying molecular signals.

Proteases are important targets in drug discovery. Some protease inhibitors are often used as anti-virus drugs and anti-cancer drugs. MCE offers a unique collection of 617 protease inhibitors. MCE Protease Inhibitor Library is critical for drug discovery and development.

Kinase is an enzyme that adds phosphate groups to other molecules. This process is known as phosphorylation. Protein phosphorylation is a key aspect in the regulation of a large number of cellular processes including cellular division, metabolism, signal transduction, and so on. There are over 500 kinases encoded by the human genome and it has been estimated that kinases regulate approximately 50% of cellular functions. Kinases are a large group of drug targets in drug discovery. Kinase inhibitors are an important class of drugs that block certain enzymes involved in diseases such as cancer and inflammatory disorders.

Kinase inhibitor library designed by MCE contains 2,842 kinase inhibitors and regulators mainly targeting protein kinases (VEGFR, EGFR, BTK, CDK, Akt, etc.), lipid kinases (PI3K, PI4K, SK, etc.) and carbohydrate kinases (Hexokinase), and is a useful tool for kinase drug discovery and related research.

Epigenetics refers to changes in phenotype that are not rooted in DNA sequence. Many types of epigenetic processes have been identified, including DNA methylation, alteration in the structure of histone proteins and gene regulation by small noncoding microRNAs. Modification of DNA, protein, or RNA, resulting in changes to the function and/or regulation of these molecules, without altering their primary sequences, reveals the complexities of cellular differentiation, embryology, the regulation of gene expression, aging, cancer, and other diseases.

MCE provide a unique collection of 1,340 epigenetics-related compounds that can be used in the research of the related diseases.

Most of molecules enter or leave cells mainly via membrane transport proteins, which play important roles in several cellular functions, including cell metabolism, ion homeostasis, signal transduction, the recognition process in the immune system, energy transduction, etc. There are three major types of transport proteins, ATP-powered pumps, channel proteins and transporters. Transport proteins such as channels and transporters play important roles in the maintenance of intracellular homeostasis, and mutations in these transport protein genes have been identified in the pathogenesis of a number of hereditary diseases. In the central nervous system, ion channels have been linked to, but not limited to, many diseases such asataxias, paralyses, epilepsies, and deafness. This indicates the roles of ion channels in the initiation and coordination of movement, sensory perception, and encoding and processing of information. Ion channels are a major class of drug targets in drug development.

MCE designs a unique collection of 1,518 smal-molecule modulators that can be used for the research of Ion Channel and Membrane Transporter or high throughput screening (HTS) related drug discovery.

The cytoskeleton is responsible for contraction, cell motility, movement of organelles and vesicles through the cytoplasm, cytokinesis, intracellular signal transduction, and many other functions that are essential for cellular homeostasis and survival. It accomplishes these tasks through three basic structures: F-actin, microtubules, and intermediate filaments (IFs). The cytoskeleton is a dynamic structure where the three major filaments and tubules are under the influence of proteins that regulate their length, state of polymerization, and level of cross-linking. Since cytoskeleton is involved in virtually all cellular processes, cytoskeletal protein aberrations are the underlying reason for many pathological phenotypes, including several cardiovascular disease syndromes, neurodegeneration, cancer, liver cirrhosis, pulmonary fibrosis, and blistering skin diseases.

MCE designs a unique collection of 1,372 cytoskeleton-related compounds mainly focusing on the key targets in the cytoskeleton signal pathway and can be used in the research of cytoskeleton signal pathway and related diseases.

The transforming growth factor beta (TGF-β) signaling pathway is involved in many cellular processes in both the adult organism and the developing embryo including cell growth, cell differentiation, apoptosis, cellular homeostasis and other cellular functions. The TGF-β superfamily comprises TGF-βs, bone morphogenetic proteins (BMPs), activins and related proteins. Signaling begins with the binding of a TGF beta superfamily ligand to a TGF beta type II receptor. The type II receptor is a serine/threonine receptor kinase, which catalyzes the phosphorylation of the Type I receptor. The type I receptor then phosphorylates receptor-regulated SMADs (R-SMADs) which can now bind the coSMAD (e.g. SMAD4). R-SMAD/coSMAD complexes accumulate in the nucleus where they act as transcription factors and participate in the regulation of target gene expression. Deregulation of TGF-β signaling contributes to developmental defects and human diseases, including cancers, some bone diseases, chronic kidney disease, etc.

MCE designs a unique collection of 253 TGF-beta/Smad signaling pathway compounds. TGF-beta/Smad Compound Library acts as a useful tool for TGF-beta/Smad-related drug screening and disease research.

Oxygen homeostasis regulation is the most fundamental cellular process for adjusting physiological oxygen variations, and its irregularity leads to various human diseases, including cancer. Hypoxia is closely associated with cancer development, and hypoxia/oxygen-sensing signaling plays critical roles in the modulation of cancer progression.

Hypoxia-inducible factor 1 (HIF-1) is a transcription factor that functions as a master regulator of oxygen homeostasis. A variety of HF-1 target genes have been identified thus far which encode proteins that play key roles in critical developmental and physiological processes including angiogenesis/vascular remodeling, erythropoiesis, glucose transport, glycolysis, iron transport, and cell proliferation/survival.

HIF-1 is a heterodimeric transcription factor consisting of a constitutively expressed β-subunit and an oxygen-regulated α-subunit. The unique feature of HIF-1 is the regulation of HIF-1α expression and activity based upon the cellular O₂ concentration. Under normoxic conditions, hydroxylation of HIF-1α on these different proline residues is essential for HIF proteolytic degradation by promoting interaction with the von Hippel-Lindau tumor-suppressor protein (pVHL) through hydrogen bonding to the hydroxyproline-binding pocket in the pVHL β-domain. As oxygen levels decrease, hydroxylation of HIF decreases; HIF-1α then no longer binds pVHL, and becomes stabilized, allowing more of the protein to translocate to the cell’s nucleus, where it acts as a transcription factor, upregulating (often within minutes) the production of proteins that stimulate blood perfusion in tissues and thus tissue oxygenation.

MCE offers a unique collection of 2,742 oxygen sensing related compounds targeting HIF/HIF Prolyl-Hydroxylase, MAPK/ERK, PI3K/AKT signaling pathways, etc. MCE Oxygen Sensing Compound Library is a useful tool to study hypoxia, oxidative stress and discover new anti-cancer drugs.

Antibiotics are types of antimicrobial products used for the treatment and prevention of bacterial infections. Antibiotics can kill or inhibit bacterial growth. Although the target of an antibiotic is bacteria, some antibiotics also attack fungi and protozoans. However, antibiotics rarely have an effect on viruses. The major mechanism underlying antibiotics is the inhibition or regulation of enzymes involved in cell wall biosynthesis, nucleic acid metabolism and repair, protein synthesis, or disruption of membrane structure. Many of these cellular functions targeted by antibiotics are most active in multiplying cells. Since there is often overlap in these functions between prokaryotic bacterial cells and eukaryotic mammalian cells, it is not surprising that some antibiotics have also been found to be useful as anticancer agents.

MCE supplies a unique collection of 688 antibiotics, including penicillins, cephalosporins, tetracyclines, macrolides, etc. MCE Antibiotics Library is a useful tool for anti-bacterial or anti-cancer drugs discovery.

MAPK families play an important role in complex cellular programs like proliferation, differentiation, development, transformation, and apoptosis. In mammalian cells, four MAPK families have been clearly characterized: ERK1/2, C-Jun N-terminal kinse/stress-activated protein kinase (JNK/SAPK) , p38 kinase and ERK5. They respond to different signals. Each MAPK-related cascade consists of three enzymes that are activated in series: a MAPK kinase kinase (MAPKKK), a MAPK kinase (MAPKK) and a MAP kinase (MAPK). MAPK signaling pathways has been implicated in the development of many human diseases including Alzheimer's disease (AD), Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS) and various types of cancers.

MCE designs a unique collection of 569 MAPK signaling pathway inhibitors that act as a useful tool for MAPK-related drug screening and disease research.

The PI3K/Akt/mTOR pathway controls many cellular processes that are important for the formation and progression of cancer, including apoptosis, transcription, translation, metabolism, angiogenesis, and cell cycle progression. Every major node of this signaling network is activated in a wide range of human tumors. Mechanisms for the pathway activation include activation of receptor tyrosine kinases (RTKs) upstream of PI3K, mutation or amplification of PIK3CA encoding p110α catalytic subunit of PI3K, mutation or loss of PTEN tumor suppressor gene, and mutation or amplification of Akt1. Once the pathway is activated, signaling through Akt can stimulate a series of substrates including mTOR which is involved in protein synthesis. Thus, inhibition of this pathway is an attractive concept for cancer prevention and/or therapy. Currently some mTOR inhibitors are approved for several indications, and there are several novel PI3K/Akt/mTOR inhibitors in clinical trials.

MCE owns a unique collection of 616 compounds that can be used for PI3K/Akt/mTOR pathway research. PI3K/Akt/mTOR Compound Library also acts as a useful tool for anti-cancer drug discovery.

Stem cells, which are found in all multi-cellular organisms, can divide and differentiate into diverse special cell types and can self-renew to produce more stem cells. To be useful in therapy, stem cells must be converted into desired cell types as necessary which is called induced differentiation or directed differentiation. Understanding and using signaling pathways for differentiation is an important method in successful regenerative medicine. Small molecules or growth factors induce the conversion of stem cells into appropriate progenitor cells, which will later give rise to the desired cell type. There is a variety of signal molecules and molecular families that may affect the establishment of germ layers in vivo, such as fibroblast growth factors (FGFs); the wnt family or superfamily of transforming growth factors β (TGFβ) and bone morphogenetic proteins (BMP). Unfortunately, for now, a high cost of recombinant factors is likely to limit their use on a larger scale in medicine. The more promising technique focuses on the use of small molecules. These small molecules can be used for either activating or deactivating specific signaling pathways. They enhance reprogramming efficiency by creating cells that are compatible with the desired type of tissue. It is a cheaper and non-immunogenic method.

MCE Differentiation Inducing Compound Library contains a unique collection of 1,554 compounds that act on signaling pathways for differentiation. These compounds are potential stimulators for induced differentiation. This library is a useful tool for researching directed differentiation and regenerative medicine.