Taylor Clinton A, Jung Ji-Ung, Gallolu Kankanamalage Sachith, Li Justin, Grzemska Magdalena, Jaykumar Ankita B, Earnest Svetlana, Stippec Steve, Saha Purbita, Sauceda Eustolia, Cobb Melanie H
Department of Pharmacology, UT Southwestern Medical Center, Dallas, 75390, TX, USA.
STARS Summer Research Program, UT Southwestern Medical Center, Dallas, 75390, TX, USA.
Commun Biol. 2025 Sep 5;8(1):1335. doi: 10.1038/s42003-025-08551-5.
The WNK-OSR1/SPAK protein kinase pathway regulates ion homeostasis and cell volume, but its other functions are not well understood. To discover undefined signaling functions, we utilized experimentally-derived binding specificity to predict interactions and relative affinities with the conserved C-terminal (CCT) domains of OSR1 and SPAK, which bind short linear motifs. The upstream kinases WNKs 1-4 and their relatives, the pseudokinases NRBP1/2, also contain CCT-like domains which have conserved folds and motif binding pockets. Motifs were scored using peptide arrays, conservation, cytosolic localization, and solvent accessibility. Out of nearly 3700 motifs in the human proteome, 90% of previously published motifs ranked in the top 2% of those predicted. Interactions with selected candidates, including TSC22D1 and CAVIN1, were validated, and their localization and/or modifications were coupled to changes in WNK1 signaling. We also identified additional motif variants and confirmed binding to the NRBP1 CCT-like domain. Our results stress the diverse functionality of CCT/CCT-like domains and implicates unexpected interactions driving WNK biology.
WNK-OSR1/SPAK蛋白激酶途径调节离子稳态和细胞体积，但其其他功能尚未完全了解。为了发现未明确的信号功能，我们利用实验得出的结合特异性来预测与OSR1和SPAK保守C末端（CCT）结构域的相互作用和相对亲和力，这些结构域结合短线性基序。上游激酶WNK1-4及其亲属，即假激酶NRBP1/2，也含有具有保守折叠和基序结合口袋的CCT样结构域。使用肽阵列、保守性、胞质定位和溶剂可及性对基序进行评分。在人类蛋白质组中近3700个基序中，90%的先前发表的基序在预测的前2%中排名。与包括TSC22D1和CAVIN1在内的选定候选物的相互作用得到了验证，并且它们的定位和/或修饰与WNK1信号的变化相关联。我们还鉴定了额外的基序变体，并证实了与NRBP1 CCT样结构域的结合。我们的结果强调了CCT/CCT样结构域的多种功能，并暗示了驱动WNK生物学的意外相互作用。
