Department of Microbiology, St. Marianna University School of Medicine, Sugao 2-16-1 Miyamae, Kawasaki 216-8511, Japan.
Department of Biomaterials, Faculty of Dental Science, Kyushu University, 3-1-1 Maidashi, Higashi-Ku, Fukuoka 812-8582, Japan.
FEBS Lett. 2014 Jun 13;588(13):2129-32. doi: 10.1016/j.febslet.2014.04.038. Epub 2014 May 9.
G protein-coupled receptor kinases (GRKs) control the signaling and activation of G protein-coupled receptors through phosphorylation. In this study, consensus substrate motifs for GRK2 were identified from the sequences of GRK2 protein substrates, and 17 candidate peptides were synthesized to identify peptide substrates with high affinity for GRK2. GRK2 appears to require an acidic amino acid at the -2, -3, or -4 positions and its consensus phosphorylation site motifs were identified as (D/E)X1-3(S/T), (D/E)X1-3(S/T)(D/E), or (D/E)X0-2(D/E)(S/T). Among the 17 peptide substrates examined, a 13-amino-acid peptide fragment of β-tubulin (DEMEFTEAESNMN) showed the highest affinity for GRK2 (Km, 33.9 μM; Vmax, 0.35 pmol min(-1) mg(-1)), but very low affinity for GRK5. This peptide may be a useful tool for investigating cellular signaling pathways regulated by GRK2.
G 蛋白偶联受体激酶（GRKs）通过磷酸化来控制 G 蛋白偶联受体的信号转导和激活。在这项研究中，从 GRK2 蛋白底物的序列中鉴定出了 GRK2 的共有底物基序，并合成了 17 个候选肽，以鉴定与 GRK2 具有高亲和力的肽底物。GRK2 似乎需要在-2、-3 或-4 位置具有酸性氨基酸，其共有磷酸化位点基序被鉴定为（D/E）X1-3（S/T）、（D/E）X1-3（S/T）（D/E）或（D/E）X0-2（D/E）（S/T）。在研究的 17 个肽底物中，β-微管蛋白的 13 个氨基酸肽片段（DEMEFTEAESNMN）对 GRK2 表现出最高的亲和力（Km，33.9 μM；Vmax，0.35 pmol min(-1) mg(-1)），但对 GRK5 的亲和力非常低。该肽段可能是研究 GRK2 调节的细胞信号通路的有用工具。
