Mitochondria are dynamic organelles with bilayer membranes. Mitochondria have multiple functions, not only providing energy to cells through oxidative phosphorylation to produce ATP, but also involved in regulating processes such as calcium homeostasis, reactive oxygen species (ROS) production, cellular stress response and cell death. Mitochondria play a key role in maintaining cellular health and viability, and their dysfunction not only contributes to the development of many human diseases such as neurodegenerative diseases, cardiovascular diseases, obesity and type II diabetes, but also reduces oocyte quality and early embryonic development in animals. Mitochondrial function is dependent on mitochondrial proteome integrity and homeostasis.
The majority of the mitochondrial proteome is encoded by the nuclear genome and is transcribed and translated in the cytoplasm and then translocated to mitochondria-specific sites by transposase. Mitochondrial DNA (mtDNA) encodes only 13 mitochondrial proteins, which are transcribed and translated within the mitochondria and become important protein components of the respiratory chain complex. mtDNA also encodes 2 ribosomal RNAs and 22 transfer RNAs, which can ensure the smooth expression of the respiratory chain complex proteins it encodes. In order for cellular mitochondria to encode protein genes for expression, mitochondria possess protein systems that enable the replication, transcription and translation of their DNA. These protein components are mainly encoded by the nuclear genome, which accounts for about 1/3 of the mitochondrial proteome. studies have speculated that the nuclear genome encodes about 250 proteins that play an important role in maintaining the expression of the mitochondrial genome.
Mitochondria are dynamic organelles with a bilayer membrane, which are divided from outside to inside into outer mitochondrial membrane (OMM), inner mitochondrial membrane (IMM), intermembrane space (IMS) and matrix. Current studies suggest that the OMM contains about 140 proteins, the IMS contains about 130 soluble proteins, the mitochondrial matrix contains about 500 proteins, and the IMM contains about 800 proteins. Most of the mitochondrial proteins are localized in the IMM.
IMM contains all respiratory chain complexes I, II, III, IV and ATP synthases encoded by the nuclear and mitochondrial genomes. Among them, respiratory chain complex I is the largest respiratory complex and intercalates with other complexes to form multiple supercomplexes. The proportion of different supercomplexes present in the mitochondria is constantly adjusted to meet the specific energy requirements of the cell in different growth states. In addition, IMM also contains protein systems such as mitochondrial contact sites and crag tissue systems, endosomal translocases and a variety of proteases and protein processing complexes.
Recent studies have revealed that mitochondria also contain many microproteins, which are mainly localized in OMM or IMM. some of these proteins are involved in the assembly of respiratory chain complexes, translation of mtDNA, mitochondrial fatty acid oxidation and endoplasmic reticulum stress response. the functions of more microproteins still need to be explored.
Creative Proteomics provides a one-stop service for mitochondrial proteomics, aiming to provide a comprehensive analysis of mitochondria from a holistic perspective, including analysis of dynamic changes in mitochondrial protein composition, expression levels, and modification status; elucidation of expression and functional patterns of all proteins in mitochondria; and protein-protein interaction analysis. It provides an important theoretical basis for analyzing the physiological functions of mitochondria, exploring the pathogenesis of mitochondria-related diseases, and promoting the development of mitochondria-targeted drugs.
