title: N-terminal acetylation of annexin A2 is required for S100A10 binding.
abstract: Annexin A2 (AnxA2), a Ca2+-regulated phospholipid binding protein involved in membrane-cytoskeleton contacts and membrane transport, exists in two physical states, as a monomer or in a heterotetrameric complex mediated by S100A10. Formation of the AnxA2-S100A10 complex is of crucial regulatory importance because only the complex is firmly anchored in the plasma membrane, where it functions in the plasma membrane targeting/recruitment of certain ion channels and receptors. The S100A10 binding motif is located in the first 12 residues of the AnxA2 N-terminal domain, but conflicting reports exist as to the importance of N-terminal AnxA2 acetylation with regard to S100A10 binding. We show here that AnxA2 is subject to N-terminal modification when expressed heterologously in Escherichia coli. Met1 is removed and Ser2 is acetylated, yielding the same modification as the authentic mammalian protein. Bacterially expressed and N-terminally acetylated AnxA2 binds S100A10 with an affinity comparable to AnxA2 from porcine tissue and is capable of forming the AnxA2-S100A10 heterotetramer. Complex formation is competitively inhibited by acetylated but not by non-acetylated peptides covering the N-terminal AnxA2 sequence. These results demonstrate that N-terminal acetylation of AnxA2 is required for S100A10 binding and that this common eukaryotic modification is also obtained upon expression in bacteria.
authors.affiliation: Institute of Medical Biochemistry, ZMBE, University of Münster, von-Esmarch-Str. 56, D-48149 Münster, Germany.
authors.forename: Ali Reza
authors.initials: AR
authors.lastname: Nazmi
authors.forename: Gabriel
authors.initials: G
authors.lastname: Ozorowski
authors.forename: Milena
authors.initials: M
authors.lastname: Pejic
authors.forename: Julian P
authors.initials: JP
authors.lastname: Whitelegge
authors.forename: Volker
authors.initials: V
authors.lastname: Gerke
authors.forename: Hartmut
authors.initials: H
authors.lastname: Luecke
mesh_terms: D000107:Acetylation; D017306:Annexin A2 / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics; D006801:Humans; D011485:Protein Binding; D021381:Protein Transport; D009418:S100 Proteins / Q000378:metabolism*; D000099248:S100 Calcium Binding Protein A10
chemical_list: D017306:Annexin A2; D009418:S100 Proteins; D000099248:S100 Calcium Binding Protein A10