Phosphoprotein

thumb|Serine in an amino acid chain, before and after phosphorylation.

A '''phosphoprotein''' is a protein that is posttranslationally modified by the attachment of either a single phosphate group, or a complex molecule such as 5'-phospho-DNA, through a phosphate group. The target amino acid is most often serine, threonine, or tyrosine residues (mostly in eukaryotes), or aspartic acid or histidine residues (mostly in prokaryotes).<ref>[https://www.uniprot.org/keywords/KW-0597 Keyword - Phosphoprotein]</ref>

==Biological function== The phosphorylation of proteins is a major regulatory mechanism in cells.<ref name=EV/><ref name="Cozzon_1988">{{cite journal | author = Cozzone AJ | title = Protein phosphorylation in prokaryotes | journal = Annu. Rev. Microbiol. | volume = 42 | pages = 97–125 | year = 1988 | pmid = 2849375 | doi = 10.1146/annurev.mi.42.100188.000525 }}</ref>

==Clinical significance== Phosphoproteins have been proposed as biomarkers for breast cancer.<ref name=LB>[http://www.genengnews.com/gen-news-highlights/liquid-biopsy-could-get-boost-from-phosphoproteins/81254064 Liquid Biopsy Could Get Boost from Phosphoproteins. 2017]</ref><ref name=EV>[http://www.pnas.org/content/114/12/3175.abstract Phosphoproteins in extracellular vesicles as candidate markers for breast cancer]</ref>

==See also== * Protein phosphorylation * Phosphoserine

==References== {{reflist}}

{{Authority control}}

Category:Phosphoproteins

{{protein-stub}}