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Protein translational modifications，PTMs - Coggle Diagram
Protein translational modifications，PTMs
covalent addition of functional groups or proteins，proteolytic cleavage of regulatory subunits, or egradation of entire proteins.
Phosphorylation
Reversible; principally on serine, threonine or tyrosine residues cell cycle, growth, apoptosis and signal transduction pathways
glycosylation
effects on protein folding, conformation, distribution, stability and activity.
nuclear transcription factors： monosaccharide modifications
cell surface receptors： complex branched polysaccharide changes
cell surface and secreted proteins： Carbohydrates in the
form of aspargine-linked (N-linked) or serine/threonine-linked (O-linked) oligosaccharides
ubiquitination
26S proteasome that catalyzes the degradation of the ubiquitinated protein and the recycling of ubiquitin
Ubiquitin is an 8-kDa polypeptide consisting of 76 amino acids； s appended to the ε-NH2
of lysine in target proteins via the C-terminal glycine of ubiquitin
nitrosylation
methylation
epigenetic regulation
The transfer of one-carbon methyl groups to nitrogen or oxygen (N- and O-methylation, respectively) to amino acid side chains
increases the hydrophobicity of the protein and can neutralize a negative amino acid charge when bound to carboxylic acids
Methylation is :mediated by methyltransferases, and S-adenosyl methionine (SAM) is the primary methyl group donor.
N-methylation is irreversible, O-methylation
is potentially reversible.
histone methylation and demethylation influences the availability of DNA for transcription
acetylation
N-acetylation, or the transfer of an acetyl group to nitrogen； irreversible and reversible mechanisms
N 端乙酰化需要 N 端蛋氨酸被蛋氨酸氨基肽酶 (MAP) 裂解，然后用 N-乙酰基转移酶 (NAT) 用乙酰辅酶 a 的乙酰基取代氨基酸。这种类型的乙酰化是共翻译的
N-terminal acetylation requires the cleavage of the N-terminal methionine by methionine aminopeptidase (MAP) before replacing the amino acid with an acetyl group from acetyl-CoA by N-acetyltransferase (NAT) enzymes； This type of acetylation is co-translational,
. Histone acetylation is a reversible event
that reduces chromosomal condensation to promote transcriptionand the acetylation of these lysine residues is regulated by transcription factors that contain histone acetyltransferase (HAT) activity
While transcription factors with HAT activity act as transcription co-activators, histone deacetylase (HDAC) enzymes are co-repressors that reverse the effects of acetylation by reducing the level of lysine acetylation and increasing chromosomal condensation.
lipidation
S-palmitoylation
N-terminal myristoylation
C-terminal glycosyl phosphatidylinositol (GPI) anchor
target proteins to membranes in organelles (endoplasmic reticulum [ER], Golgi apparatus, mitochondria), vesicles (endosomes, lysosomes) and the plasma membrane.
每种类型的修饰使蛋白质具有不同的膜亲和力，尽管所有类型的脂化增加了蛋白质的疏水性，从而增加了其对膜的亲和力。不同类型的脂类也不是相互排斥的，因为两种或两种以上的脂类可以附着在给定的蛋白质上。
distinct membrane affinities, although all types of
lipidation increase the hydrophobicity of a protein and thus its affinity for membranes
S-prenylation
proteolysis
single genes encode multiple proteins.--different mRNA transcripts: Genomic recombination, transcription initiation at alternative promoters, differential transcription termination, and alternative splicing of the transcript
protein post-translational modifications (PTMs): chemical modifications in functional proteomic, because they regulate activity, localization, and interaction with other cellular molecules such as proteins, nucleic acids, lipids and cofactors.
amino acid side chains or peptide linkages; enzymatic activity
challenge: the development of specific detection
and purification methods