Widowati Esti Wahyu, Bamberg-Lemper Simone, Becker Walter
Institute of Pharmacology and Toxicology, RWTH Aachen University, Aachen, Germany.
Chemistry Study Program, Faculty of Science and Technology, State Islamic University (UIN) Sunan Kalijaga, Yogyakarta, Indonesia.
BMC Res Notes. 2018 May 15;11(1):297. doi: 10.1186/s13104-018-3416-4.
Dual specificity tyrosine phosphorylation-regulated kinases (DYRK) contain a characteristic sequence motif (DYRK homology box, DH box) that is located N-terminal of the catalytic domain and supports the autophosphorylation of a conserved tyrosine during maturation of the catalytic domain. Two missense mutations in the DH box of human DYRK1B were recently identified as causative of a rare familiar form of metabolic syndrome. We have recently shown that these amino acid exchanges impair maturation of the kinase domain. Here we report the characterization of DYRK1A point mutants (D138P, K150C) that correspond to the pathogenic DYRK1B variants (H90P, R102C).
When expressed in HeLa cells, DYRK1A-D138P and K150C showed no significant difference from wild type DYRK1A regarding the activating tyrosine autophosphorylation or catalytic activity towards exogenous substrates. However, both DYRK1A variants were underphosphorylated on tyrosine when expressed in a bacterial cell free in vitro translation system. These results suggest that D138 and K150 participate in the maturation of the catalytic domain of DYRK1A albeit the mutation of these residues is compensated under physiological conditions.
双特异性酪氨酸磷酸化调节激酶（DYRK）包含一个特征性序列基序（DYRK同源框，DH框），该基序位于催化结构域的N端，并在催化结构域成熟过程中支持保守酪氨酸的自磷酸化。最近，人类DYRK1B的DH框中的两个错义突变被确定为一种罕见的家族性代谢综合征的病因。我们最近表明，这些氨基酸交换会损害激酶结构域的成熟。在此，我们报告与致病性DYRK1B变体（H90P、R102C）相对应的DYRK1A点突变体（D138P、K150C）的特征。
当在HeLa细胞中表达时，DYRK1A-D138P和K150C在激活酪氨酸自磷酸化或对外源底物的催化活性方面与野生型DYRK1A没有显著差异。然而，当在无细胞体外翻译系统中表达时，这两种DYRK1A变体在酪氨酸上的磷酸化程度都较低。这些结果表明，D138和K150参与了DYRK1A催化结构域的成熟，尽管这些残基的突变在生理条件下得到了补偿。
