Recent genetic studies in Drosophila identified Kibra as a novel regulator of the Hippo pathway, which controls tissue growth and tumorigenesis by inhibiting cell proliferation and promoting apoptosis. The cellular function and regulation of human KIBRA remain largely unclear. Here, we show that KIBRA is a phosphoprotein and that phosphorylation of KIBRA is regulated in a cell cycle-dependent manner with the highest level of phosphorylated KIBRA detected in mitosis. We further demonstrate that the mitotic kinases Aurora-A and -B phosphorylate KIBRA both in vitro and in vivo. We identified the highly conserved Ser(539) as the primary phosphorylation site for Aurora kinases. Moreover, we found that wild-type, but not catalytically inactive, protein phosphatase 1 (PP1) associates with KIBRA. PP1 dephosphorylated Aurora-phosphorylated KIBRA. KIBRA depletion impaired the interaction between Aurora-A and PP1. We also show that KIBRA associates with neurofibromatosis type 2/Merlin in a Ser(539) phosphorylation-dependent manner. Phosphorylation of KIBRA on Ser(539) plays a role in mitotic progression. Our results suggest that KIBRA is a physiological substrate of Aurora kinases and reveal a new avenue between KIBRA/Hippo signaling and the mitotic machinery.
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http://dx.doi.org/10.1074/jbc.M111.246850 | DOI Listing |
PLoS One
January 2025
Faculty of Health Sciences, Department of Public and Global Health, University of Nairobi, Nairobi, Kenya.
The absence of an accurate reference test complicates the evaluation of tuberculosis (TB) diagnostic tests among people living with Human Immunodeficiency Virus (PLWHIV). The objective of this study was to estimate (using Bayesian latent class models [BLCM]) the sensitivity (Se), specificity (Sp) and negative and positive predictive values (NPV and PPV) of sputum smear microscopy (SSM), Xpert Ultra and lipoarabinomannan antigen (LAM) tests for TB among PLWHIV in Nairobi, Kenya. This cross-sectional study enrolled a total of 190 patients aged ≥ 18 years with presumptive TB seeking treatment at the Kibra Community Health Center Comprehensive Care Centre (CCC) clinic between September 2022 and March 2023.
View Article and Find Full Text PDFAdv Sci (Weinh)
December 2024
Institute of Cancer Stem Cell, Dalian Medical University Cancer Center, Dalian, 116044, China.
Elevated uptake of saturated fatty acid palmitic acid (PA) is associated with tumor metastasis; however, the precise mechanisms remain partially understood, hindering the development of therapy for PA-driven tumor metastasis. The Hippo-Yes-associated protein (Hippo/YAP) pathway is implicated in cancer progression. Here it is shown that a high-palm oil diet potentiates tumor metastasis in murine xenografts in part through YAP.
View Article and Find Full Text PDFJ Alzheimers Dis
November 2024
Memory Clinic, Department of Neurology, Second Faculty of Medicine, Charles University, Motol University Hospital, Prague, Czech Republic.
Background: Genetic variations in a common single nucleotide polymorphism in the ninth intron of the gene have been linked to memory performance and risk of Alzheimer's disease (AD).
Objective: We examined the risk of AD related to presence of T allele (versus homozygote) and to memory performance. The role of established genetic risk factors ε4 and Met was also considered.
Cell Rep
October 2024
Department of Neuroscience, UT Southwestern Medical Center, Dallas, TX 75390, USA; Department of Psychiatry UT Southwestern Medical Center, Dallas, TX 75390, USA; Peter O'Donnell Jr. Brain Institute, UT Southwestern Medical Center, Dallas, TX 75390, USA. Electronic address:
The WW and C2 domain-containing protein (WWC2) is implicated in several neurological disorders. Here, we demonstrate that WWC2 interacts with inhibitory, but not excitatory, postsynaptic scaffolds, consistent with prior proteomic identification of WWC2 as a putative component of the inhibitory postsynaptic density. Using mice lacking WWC2 expression in excitatory forebrain neurons, we show that WWC2 suppresses γ-aminobutyric acid type-A receptor (GABAR) incorporation into the plasma membrane and regulates HAP1 and GRIP1, which form a complex promoting GABAR recycling to the membrane.
View Article and Find Full Text PDFbioRxiv
September 2024
Department of Physiology and Pharmacology, SUNY Downstate Health Sciences University, Brooklyn, NY. 11203. USA.
Activity-dependent modifications of synaptic efficacies are a cellular substrate of learning and memory. Current theories propose that the long-term maintenance of synaptic efficacies and memory is accomplished via a positive-feedback loop at the level of production of a protein species or a protein state. Here we propose a qualitatively different theoretical framework based on negative-feedback at the level of protein elimination.
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