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MindMap Gallery Cytoplasmic matrix and endomembrane system
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Cytoplasmic matrix and endomembrane system
Cell biology - mind map of cytoplasmic matrix and endomembrane system. Cytoplasmic matrix is the colloidal substance in eukaryotic cells excluding membranous organelles, accounting for more than 50% of the total cell volume.
Edited at 2023-10-16 01:30:22
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Cytoplasmic matrix and endomembrane system
cytoplasmic matrix
definition
Colloidal substances in eukaryotic cells excluding membranous organelles
Features
Account for more than 50% of the total cell volume
Main ingredients
water
70%
protein
20%-30%
ion
Cytoskeleton
highly ordered system
Function
It is the site of many metabolic reactions in cells
Together with the cytoskeleton, it maintains cell shape, participates in cell movement, intracellular material transport, and energy and signal transmission.
Synthesis, post-translational modification, selective degradation, etc. of proteins in the cytoplasmic matrix
protein modification
The combination of coenzyme or prosthetic group with enzyme
Phosphorylation and dephosphorylation
protein glycosylation
Methylation modification
Acylation
Control protein lifespan
The first amino acid residue at the N-terminus is a signal that determines the protein's lifespan
Ubiquitination and proteasome-mediated protein degradation pathways
A mechanism that recognizes and degrades misfolded or unstable proteins
Helps denatured or misfolded proteins refold
Heat shock protein (HSP)
Endoplasmic reticulum (ER)
Features
A three-dimensional network structure formed or connected by a closed tubular or flat sac-like membrane system and its surrounding cavities
The endoplasmic reticulum accounts for about half of the cell membrane system
The volume accounts for more than 10% of the total cell volume
Classification
Rough endoplasmic reticulum (rER)
Smooth endoplasmic reticulum (sER)
other
Lamellar endoplasmic reticulum/tubular endoplasmic reticulum
Function
protein synthesis
Protein modification and processing
Glycosylation modifications that occur in the endoplasmic reticulum and Golgi apparatus (main function)
About half of all eukaryotic proteins are glycosylated
Transfer is catalyzed by oligosaccharyltransferases, whose active sites are exposed on the luminal side of the ER
Formation of disulfide bonds in the lumen of the endoplasmic reticulum
Disulfide bonds are formed and rearranged in the ER lumen by protein disulfide isomerase (PDI)
Specific proteolytic cleavage occurs in the endoplasmic reticulum, Golgi apparatus, and secretory vesicles
Protein folding and assembly
Endoplasmic reticulum stress (ERS) response
Unfolded protein response (UPR)
sterol regulatory cascade
Endoplasmic reticulum overload response (EOR)
Endoplasmic reticulum function continues to be disordered, and cells will eventually initiate apoptosis.
membrane lipid synthesis
The endoplasmic reticulum synthesizes almost all membrane lipids required by cells, including phospholipids and cholesterol. The most important phospholipid is phosphatidylcholine.
Two exceptions
Sphingomyelin and glycolipids (starts in the ER and completes in the Golgi apparatus)
Some unique lipids of mitochondrial and chloroplast membranes
Other functions of smooth endoplasmic reticulum
Steroid synthesis in endocrine cells
Detoxification of organic compounds in stem cells
Release of glucose-6-phosphate from stem cells
Store Ca
golgi apparatus
Features
Polar organelles composed of neatly arranged stacks of flat membrane vesicles
The side close to the nucleus is called the formation side or cis side, and the side facing the plasma membrane is called the maturation side or trans side.
composition
Smooth membrane vesicle and smooth mesh structure
intermediate membrane sac
Reverse membrane sac and reverse mesh structure
Function
protein
Process, sort, package and transport proteins synthesized in the endoplasmic reticulum
Participate in protein sorting
CiS sorting and transport of proteins
Endoplasmic reticulum-resident proteins return from the Golgi apparatus
Protein sorting and transport
Lysosomal enzyme packaging and sorting pathways
Mannose-6-phosphate labeling
Regulated secretory pathways such as insulin secretion
Constitutive secretion pathway such as: leukocytes secrete interleukins
Participate in protein glycosylation and modification
Protease hydrolysis
Other processes such as sulfation
Lipids
Some lipids synthesized in the endoplasmic reticulum are transported to the cytoplasmic membrane, lysosomal membrane, etc. through the Golgi apparatus.
carbohydrate
carbohydrate synthesis
lysosome
Features
A vesicle-like organelle surrounded by a single membrane and containing a variety of acid hydrolases
heterogeneous organelles
primary lysosome
Secondary lysosomes: autophagolysosomes and xenolysosomes
residual body
structure
Contains a variety of acid hydrolases, with an optimal pH of around 5.0
Acid phosphatase is a commonly used marker enzyme
Lysosomal membrane composition is special
Embedded proton pump
Has a variety of carrier proteins
Membrane proteins are highly glycosylated
effect
endocytosis
digestion-endocytosis
Phagocytosis
subtopic
autophagy
Explanation of autophagy, biological macromolecules, and damaged organelles
Microautophagy
Macroautophagy
Molecular chaperone-mediated autophagy
Diversification of lysosomal enzyme sorting pathways
M6P-dependent sorting pathway
Calcium-dependent M6P receptors on the cytoplasmic membrane bind to extracellular lysosomal enzymes
M6P-independent sorting pathway
Lysosomes and disease
lysosomal storage disease
Tay-Sachs syndrome
I cell disease
Decreased lysosomal membrane stability and related diseases caused by hydrolase spillage
Silicosis
rheumatoid arthritis
Catalosome
Features
Also called a microbody, a cell organelle surrounded by a single membrane and containing one or several oxidative enzymes.
Found in all animal cells and many plant cells
heterogeneous organelles
Organelles that directly utilize molecular oxygen in eukaryotic cells
Flavin-dependent (FAD) oxidase
Catalase (marker enzyme)
Function
animal cells
Participates in the β-oxidation of fatty acids and directly provides heat energy to cells without having to hydrolyze ATP to obtain energy.
Detoxification
plant cells
Participates in photorespiration and oxidizes glycolic acid, a by-product of photosynthesis, into glyoxylic acid and hydrogen peroxide.
In germinating seeds, beta-oxidation of fat occurs
proteasome
A macromolecular complex that degrades proteins, consisting of about 50 subunits
Ubiquitin
A small molecule globulin composed of 76 amino acid residues
Ubiquitination modification of proteins - ubiquitin molecules covalently bind to lysine residues of target proteins
three enzymes
Ubiquitin activating enzyme (E1)
Ubiquitin conjugating enzyme (E2)
Ubiquitin ligase (E3)
polyubiquitination