Identification of Ser-1275 and Ser-1309 as autophosphorylation sites of the insulin receptor.
We have identified Ser-1275 and Ser-1309 as novel serine autophosphorylation sites by direct sequencing of HPLC-purified tryptic phosphopeptides of the histidine-tagged insulin receptor kinase IRKD-HIS. The corresponding peptides (Ser-1275, amino acids 1272-1292; Ser-1309, amino acids 1305-1313) have been detected in the HPLC profiles of both the soluble kinase IRKD, which contains the entire cytoplasmic domain of the insulin receptor beta-subunit, and the insulin receptor purified from human placenta. In contrast, a kinase negative mutant, IRKD-K1018A, did not undergo phosphorylation at either the tyrosine or serine residues, strongly suggesting that insulin receptor kinase has an intrinsic activity to autophosphorylate serine residues.
Al-Hasani
H
H
Diabetes Forschungsinstitut Düsseldorf, Germany.
Eisermann
B
B
Tennagels
N
N
Magg
C
C
Passlack
W
W
Koenen
M
M
Müller-Wieland
D
D
Meyer
H E
HE
Klein
H W
HW
D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D006801:Humans; D008969:Molecular Sequence Data; D009154:Mutation; D010449:Peptide Mapping; D010748:Phosphopeptides / Q000378:metabolism; D010766:Phosphorylation; D011972:Receptor, Insulin / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D012694:Serine / Q000378:metabolism*; D012995:Solubility; D018411:Spodoptera; D013912:Threonine / Q000378:metabolism
D010748:Phosphopeptides; D011994:Recombinant Proteins; D013912:Threonine; D012694:Serine; D011972:Receptor, Insulin