Recombinant Proteins
Product List
EMC2 Human
ER Membrane Protein Complex Subunit 2 Human Recombinant
ERP27 Human
Endoplasmic Reticulum Protein 27 Human Recombinant
ERP44 Human
Endoplasmic Reticulum Protein 44 Human Recombinant
Introduction
The endoplasmic reticulum (ER) is a large, membranous organelle found in eukaryotic cells. It is involved in the synthesis, folding, modification, and transport of proteins and lipids. The ER is classified into two types: the rough endoplasmic reticulum (RER) and the smooth endoplasmic reticulum (SER). The RER is studded with ribosomes on its cytoplasmic surface, giving it a rough appearance, and is primarily involved in protein synthesis. The SER lacks ribosomes and is involved in lipid synthesis, detoxification, and calcium storage .
Key Biological Properties: The ER is a dynamic structure composed of sheets and tubules that spread throughout the cytoplasm and are contiguous with the nuclear membrane. It plays a crucial role in maintaining cellular homeostasis by regulating protein and lipid synthesis, calcium storage, and detoxification processes .
Expression Patterns and Tissue Distribution: The ER is present in all eukaryotic cells, but its abundance and structure can vary depending on the cell type and its function. For example, liver cells (hepatocytes) have an extensive ER network due to their role in detoxification and protein synthesis. Similarly, pancreatic beta cells, which secrete insulin, and activated B-lymphocytes, which produce antibodies, have prominent ER structures .
Primary Biological Functions: The ER is essential for the synthesis, folding, and modification of proteins. The RER is responsible for synthesizing proteins that are either secreted from the cell, incorporated into the cell membrane, or sent to lysosomes. The SER is involved in the synthesis of lipids, including phospholipids and cholesterol, and the detoxification of drugs and poisons .
Role in Immune Responses and Pathogen Recognition: The ER plays a role in the immune response by producing and folding proteins that are essential for the function of immune cells. For example, the ER in activated B-lymphocytes is involved in the production of antibodies, which are crucial for pathogen recognition and neutralization .
Mechanisms with Other Molecules and Cells: The ER interacts with various molecules and organelles within the cell. Proteins synthesized in the RER are transported to the Golgi apparatus for further modification and sorting. The ER also forms contact sites with the plasma membrane, mitochondria, and other organelles, facilitating the exchange of lipids and calcium ions .
Binding Partners and Downstream Signaling Cascades: The ER contains chaperone proteins that assist in the proper folding of newly synthesized proteins. Misfolded proteins are targeted for degradation through the ER-associated degradation (ERAD) pathway. The ER also plays a role in calcium signaling by releasing calcium ions into the cytoplasm in response to various stimuli .
Regulatory Mechanisms Controlling Expression and Activity: The expression and activity of ER proteins are tightly regulated at multiple levels. Transcriptional regulation involves the activation of specific genes in response to cellular signals. Post-translational modifications, such as phosphorylation and glycosylation, also play a crucial role in regulating the function of ER proteins .
Transcriptional Regulation and Post-Translational Modifications: The unfolded protein response (UPR) is a key regulatory mechanism that is activated in response to the accumulation of misfolded proteins in the ER. The UPR enhances the expression of chaperone proteins and components of the ERAD pathway to restore protein homeostasis .
Biomedical Research: The ER is a target for research in various fields, including cancer, neurodegenerative diseases, and metabolic disorders. Understanding the role of ER stress and the UPR in disease pathology can lead to the development of novel therapeutic strategies .
Diagnostic Tools and Therapeutic Strategies: ER-associated proteins can serve as biomarkers for the diagnosis of diseases. Therapeutic strategies targeting ER stress and the UPR are being explored for the treatment of diseases such as cancer, diabetes, and neurodegenerative disorders .
Role Throughout the Life Cycle: The ER plays a critical role throughout the life cycle of a cell, from development to aging and disease. During development, the ER is involved in the synthesis of proteins and lipids required for cell growth and differentiation. In aging cells, the efficiency of protein folding and the capacity of the UPR decline, leading to the accumulation of misfolded proteins and cellular dysfunction .
From Development to Aging and Disease: The ER’s role in maintaining protein homeostasis is crucial for preventing diseases associated with protein misfolding, such as Alzheimer’s disease and Parkinson’s disease. The ER also plays a role in the response to cellular stress and the regulation of apoptosis, which is important for maintaining tissue homeostasis and preventing cancer .
