Plus and minus ends of microtubules respond asymmetrically to kinesin binding by a long-range directionally driven allosteric mechanism

KIF3C: an emerging biomarker with prognostic and immune implications across pan-cancer types and its experiment validation in gastric cancer

Kinesin Family Member 3C (KIF3C) assumes a crucial role in various biological processes of specific human cancers. Nevertheless, there exists a paucity of systematic assessments pertaining to the contribution of KIF3C in human malignancies. We conducted an extensive analysis of KIF3C, covering its expression profile, prognostic relevance, molecular function, tumor immunity, and drug sensitivity. Functional enrichment analysis was also carried out. In addition, we conducted in vitro experiments to substantiate the role of KIF3C in gastric cancer (GC). KIF3C expression demonstrated consistent elevation in various tumors compared to their corresponding normal tissues. We further unveiled that heightened KIF3C expression served as a prognostic indicator, and its elevated levels correlated with unfavorable clinical outcomes, encompassing reduced OS, DSS, and PFS in several cancer types. Notably, KIF3C expression exhibited positive associations with the pathological stages of several cancers. Moreover, KIF3C demonstrated varying relationships with the infiltration of various distinct immune cell types in gastric cancer. Functional analysis outcomes indicated that KIF3C played a role in the PI3K-AKT signaling pathway. Drug sensitivity unveiled a positive relationship between KIF3C in gastric cancer and the IC50 values of the majority of identified anti-cancer drugs. Additionally, KIF3C knockdown reduced the proliferation, migration, and invasion capabilities, increased apoptosis, and led to alterations in the cell cycle of gastric cancer cells. Our research has revealed the significant and functional role of KIF3C as a tumorigenic gene in diverse cancer types. These findings indicate that KIF3C may serve as a promising target for the treatment of gastric cancer.

Road-blocker HSP disease mutation disrupts pre-organization for ATP hydrolysis in kinesin through a second sphere control

Kinesin motor proteins perform several essential cellular functions powered by the adenosine triphosphate (ATP) hydrolysis reaction. Several single-point mutations in the kinesin motor protein KIF5A have been implicated to hereditary spastic paraplegia disease (HSP), a lethal neurodegenerative disease in humans. In earlier studies, we have shown that a series of HSP-related mutations can impair the kinesin's long-distance displacement or processivity by modulating the order-disorder transition of the linker connecting the heads to the coiled coil. On the other hand, the reduction of kinesin's ATP hydrolysis reaction rate by a distal asparagine-to-serine mutation is also known to cause HSP disease. However, the molecular mechanism of the ATP hydrolysis reaction in kinesin by this distal mutation is still not fully understood. Using classical molecular dynamics simulations combined with quantum mechanics/molecular mechanics calculations, the pre-organization geometry required for optimal hydrolysis in kinesin motor bound to α/β-tubulin is determined. This optimal geometry has only a single salt-bridge (of the possible two) between Arg203-Glu236, putting a reactive water molecule at a perfect position for hydrolysis. Such geometry is also needed to create the appropriate configuration for proton translocation during ATP hydrolysis. The distal asparagine-to-serine mutation is found to disrupt this optimal geometry. Therefore, the current study along with our previous one demonstrates how two different effects on kinesin dynamics (processivity and ATP hydrolysis), caused by a different set of genotypes, can give rise to the same phenotype leading to HSP disease.