ATP allosterically stabilizes integrin-linked kinase for efficient force generation

Abstract

Significance The pseudokinase integrin-linked kinase (ILK) is a central component of focal adhesions, cytoplasmic multiprotein complexes that integrate and transduce biochemical and mechanical signals from the extracellular environment into the cell and vice versa. However, the precise molecular functions, particularly the mechanosensory properties of ILK and the significance of retained adenosine triphosphate (ATP) binding, are still unclear. Combining molecular-dynamics simulations with cell biology, we establish a role for ATP binding to pseudokinases. We find that ATP promotes the structural stability of ILK, allosterically influences the interaction between ILK and its binding partner parvin at adhesions, and enhances the mechanoresistance of this complex. On the cellular level, ATP binding facilitates efficient traction force buildup, focal adhesion stabilization, and efficient cell migration.

Insight into the mechanism of molecular recognition between human Integrin-Linked Kinase and Cpd22 and its implication at atomic level

“…In terms of RMSD, apo-ILK exhibited a mean value of 2.08 ± 0.25 Å (SD) while ILK-ATP showed a slightly lower value (1.96 ± 0.1 Å). This is in good agreement with recent studies relating ATP binding to a conformational stabilization of the ILK kinase domain, thus also validating our approach [47]. Moreover, our observation is in full agreement with experimental studies, which observed stabilization induced by ATP binding rather than gross conformational changes [7,31,47].…”

“…In our apo-ILK simulations these amino acids preserve some residual mobility along the whole dynamics. In contrast, the presence of an ATP molecule increases their mobility, especially for the Arg349 (Table 1), as previously observed and reported for the ILK-ATP complex without α-parvin [47]. Notoriously, this effect is also observed in Cpd22 bound systems, suggesting the ability of this molecule to trigger the allosteric network towards α-parvin interaction region.…”

“…This effect may be of interest from the point of view of ILK protein-protein interactions with PINCH and parvin partner adaptor proteins, as the response elicited by Cpd22 on ILK flexibility as a whole could affect PPI assembly and/or stability given the lower conformational motions. This hypothesis is supported by the previously observed effect of ATP binding, which stabilizes the pseudokinase domain, thus facilitating a more effective interaction between the focal adhesion proteins PINCH and parvin [39,47].…”

Recent advances in targeting protein kinases and pseudokinases in cancer biology

“…Although pseudokinases lack kinase activity, a growing number of them have been shown to play key roles in regulating various cellular processes (Figure 2), including MAPK signaling, actin polymerization, and the development of malignancies (Fukuda et al, 2009;Scheeff et al, 2009;Ghatak et al, 2013;Toms et al, 2013;Murphy et al, 2015;Stefely et al, 2015;Martin et al, 2022). Three principal mechanisms of kinase-independent actions have emerged, which may also occur in combination in some pseudokinases: 1) Allosteric regulation of kinase activity through heterodimerization of pseudokinase and kinase.…”

“…Inhibition of ILK has been a key strategy for many cancer treatments (Martin et al, 2022). Due to the complexity of proteinprotein interactions and a plethora of affected pathways, these programs exhibit various levels of success in their development-these include chronic lymphocytic leukemia (CLL), breast cancer, and various cancer cell lines in vitro.…”