A-kinase anchoring proteins (AKAPs) control the localization and substrate specificity of cAMP-dependent protein kinase (PKA), tetramers of regulatory (PKA-R) and catalytic (PKA-C) subunits, by binding to PKA-R subunits. Most mammalian AKAPs bind Type II PKA through PKA-RII (ref. 2), whereas dual specificity AKAPs bind both PKA-RI and PKA-RII (ref. 3). Inhibition of PKA-AKAP interactions modulates PKA signalling. Localized PKA activation in pseudopodia of migrating cells phosphorylates alpha4 integrins to provide spatial cues governing cell motility. Here, we report that the alpha4 cytoplasmic domain is a Type I PKA-specific AKAP that is distinct from canonical AKAPs in two ways: the alpha4 interaction requires the PKA holoenzyme, and is insensitive to amphipathic peptides that disrupt most PKA-AKAP interactions. We exploited type-specific PKA anchoring peptides to create genetically encoded baits that sequester specific PKA isoforms to the mitochondria and found that mislocalization of Type I, but not Type II, PKA disrupts alpha4 phosphorylation and markedly inhibits the velocity and directional persistence of cell migration.
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http://dx.doi.org/10.1038/ncb1561 | DOI Listing |
Cancer Immunol Immunother
January 2025
Department of Medical Oncology, Institut de Cancérologie de L'Ouest, 44805, Saint Herblain, France.
Front Immunol
December 2024
Department of Microbiology, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.
The functional specialization of CD4 T lymphocytes into various subtypes, including T1 and T cells, is crucial for effective immune responses. T cells facilitate B cell differentiation within germinal centers, while T1 cells are vital for cell-mediated immunity against intracellular pathogens. Integrin α4, a cell surface adhesion molecule, plays significant roles in cell migration and co-stimulatory signaling.
View Article and Find Full Text PDFHematol Oncol
January 2025
Hematology, Oncology R&D, AstraZeneca, Cambridge, UK.
Contemporary studies of Bruton tyrosine kinase inhibitor (BTKi) resistance focus on mutations in the B-cell receptor (BCR) pathway, but alternative mechanisms of resistance remain undefined. Here, we sought to identify novel predictive markers of acquired resistance to acalabrutinib, a second-generation BTKi, in patients with chronic lymphocytic leukemia (CLL). Clinical samples from 41 patients with relapsed/refractory or treatment-naive CLL receiving acalabrutinib as part of a clinical trial (NCT02029443) were divided into two groups: those who continued to respond to treatment (NP, n = 23) and those who developed progressive disease on acalabrutinib therapy (PD, n = 18).
View Article and Find Full Text PDFMult Scler J Exp Transl Clin
December 2024
Department of Neurosciences, Concord Repatriation General Hospital, Sydney, Australia.
Intermediate uveitis (IU) may be associated with multiple sclerosis (MS), with both conditions possibly sharing pathogenic mechanisms Two patients presented with bilateral IU. Despite targeted uveitis treatment with corticosteroids and methotrexate, both had ongoing disease activity with symptoms, and fluorescein angiographic abnormalities. Both were subsequently identified to have radiologically isolated MS in the absence of clinical demyelination.
View Article and Find Full Text PDFEMBO Rep
January 2025
Centre for Parasitology, School of Infection and Immunity, University of Glasgow, Glasgow, G12 8TA, UK.
The immunoregulatory cytokine TGF-β is pleiotropic due to the near-ubiquitous expression of the TGF-β receptors TβRI and TβRII on diverse cell types. The helminth parasite Heligmosomoides polygyrus has convergently evolved a family of TGF-β mimics (TGMs) that bind both these receptors through domains 1-3 of a 5-domain protein. One member of this family, TGM4, differs from TGF-β in acting in a cell-specific manner, failing to stimulate fibroblasts, but activating SMAD phosphorylation in macrophages.
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