LIMK2, a serine-specific kinase, is a key regulator of actin dynamics. It belongs to the LIM kinase family and is involved in the Rho family GTPase signal transduction pathways. By phosphorylating cofilin, an actin-depolymerizing factor, it controls actin filament and microtubule turnover, thus playing a crucial role in many biological processes such as cell cycle, cell migration, and neuronal differentiation [1,4].

In various diseases, especially cancers, LIMK2 has been extensively studied. In castration-resistant prostate cancer (CRPC), inducible knockdown of LIMK2 fully reverses tumorigenesis. It was found that LIMK2 phosphorylates and degrades NKX3.1, a prostate-specific tumor suppressor, promoting oncogenicity in CRPC cells and in vivo [2]. In melanoma, genetic or pharmacological inhibition of LIMK2 impairs tumor growth and metastasis. The LIMK2→G3BP1→ESM1 pathway was identified as a facilitator of melanoma tumor growth and metastasis [3]. In triple-negative breast cancer (TNBC), shRNA-mediated LIMK2 knockdown or its pharmacological inhibition blocks metastatic attributes of TNBC cells by inhibiting the phosphorylation and activity of SRPK1 [6]. In airway smooth muscle, LIMK2-deficient mice show approximately 30% inhibition in maximal force, indicating that LIMK2 is necessary for F-actin dynamics and force transduction [5].

In conclusion, LIMK2 is essential for regulating actin dynamics and participates in multiple biological processes. The use of gene knockout or conditional knockout mouse models has revealed its significant role in cancer development, such as in CRPC, melanoma, and TNBC, as well as in airway smooth muscle function. These findings suggest that LIMK2 could be a potential therapeutic target in related diseases.

References:

1. Shah, Kavita, Cook, Mason. 2023. LIMK2: A Multifaceted kinase with pleiotropic roles in human physiology and pathologies. In Cancer letters, 565, 216207. doi:10.1016/j.canlet.2023.216207. https://pubmed.ncbi.nlm.nih.gov/37141984/

2. Sooreshjani, Moloud A, Nikhil, Kumar, Kamra, Mohini, Kumar, Dinesh, Shah, Kavita. 2021. LIMK2-NKX3.1 Engagement Promotes Castration-Resistant Prostate Cancer. In Cancers, 13, . doi:10.3390/cancers13102324. https://pubmed.ncbi.nlm.nih.gov/34066036/

3. Malvi, Parmanand, Reddy, Dhana Sekhar, Kumar, Raj, Zhang, Xuchen, Wajapeyee, Narendra. 2023. LIMK2 promotes melanoma tumor growth and metastasis through G3BP1-ESM1 pathway-mediated apoptosis inhibition. In Oncogene, 42, 1478-1491. doi:10.1038/s41388-023-02658-x. https://pubmed.ncbi.nlm.nih.gov/36922679/

4. Villalonga, Elodie, Mosrin, Christine, Normand, Thierry, Bénédetti, Hélène, Vallée, Béatrice. 2023. LIM Kinases, LIMK1 and LIMK2, Are Crucial Node Actors of the Cell Fate: Molecular to Pathological Features. In Cells, 12, . doi:10.3390/cells12050805. https://pubmed.ncbi.nlm.nih.gov/36899941/

5. Li, Yeqiong, Zhou, Yuwei, Wang, Pei, Zhang, Xue-Na, Zhu, Min-Sheng. 2021. LIMK2 is required for membrane cytoskeleton reorganization of contracting airway smooth muscle. In Journal of genetics and genomics = Yi chuan xue bao, 48, 452-462. doi:10.1016/j.jgg.2021.04.014. https://pubmed.ncbi.nlm.nih.gov/34353741/

6. Malvi, Parmanand, Janostiak, Radoslav, Chava, Suresh, Gupta, Romi, Wajapeyee, Narendra. 2020. LIMK2 promotes the metastatic progression of triple-negative breast cancer by activating SRPK1. In Oncogenesis, 9, 77. doi:10.1038/s41389-020-00263-1. https://pubmed.ncbi.nlm.nih.gov/32859889/