98%
921
2 minutes
20
Members of the mammalian phosphoinositide-3-OH kinase (PI3K) family of proteins are critical regulators of various cellular process including cell survival, growth, proliferation, and motility. Oncogenic activating mutations in the p110alpha catalytic subunit of the heterodimeric p110/p85 PI3K enzyme are frequent in human cancers. Here we show the presence of frequent mutations in p85alpha in colon cancer, a majority of which occurs in the inter-Src homology-2 (iSH2) domain. These mutations uncouple and retain p85alpha's p110-stabilizing activity, while abrogating its p110-inhibitory activity. The p85alpha mutants promote cell survival, AKT activation, anchorage-independent cell growth, and oncogenesis in a p110-dependent manner.
Download full-text PDF |
Source |
---|---|
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2804903 | PMC |
http://dx.doi.org/10.1016/j.ccr.2009.10.016 | DOI Listing |
Leukemia
September 2025
Department of Hematology of First Affiliated Hospital, and Department of Public Health, Zhejiang University School of Medicine, Hangzhou, China.
BCR::ABL1 oncofusion protein drives Philadelphia-chromosome positive acute lymphoblastic leukemia (Ph+ ALL), making it a critical therapeutic target. Tyrosine kinase inhibitors (TKIs) targeting BCR::ABL1 have revolutionized the treatment of Ph+ ALL patients. However, mutations in the kinase domain of BCR::ABL1 commonly impair the sensitivity to TKIs, resulting in drug resistance and poor prognosis in Ph+ ALL.
View Article and Find Full Text PDFInt J Med Sci
July 2025
Department of Laboratory Medicine, Zhongnan Hospital of Wuhan University, Wuhan, Hubei, China.
The gene encodes the class IA PI3K regulatory subunit p85α, which is frequently altered in cancer. functions as a tumor suppressor by stabilizing and inhibiting the catalytic activity of p110, and it directly binds to and enhances the activity of the PTEN lipid phosphatase. Aberrations in the gene are associated with poor prognosis in cancer; available data underscore the significant role of mutations in mediating tumorigenesis by promoting the signaling of the PI3K/AKT/mTOR pathway.
View Article and Find Full Text PDFJ Diabetes Investig
August 2025
Division of Diabetes and Endocrinology, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe, Japan.
Aims/introduction: Phosphatidylinositol 3-kinase (PI3K) plays a key role in insulin signaling, and mutations in PIK3R1, which encodes a regulatory subunit (p85α) of this enzyme, are responsible for SHORT syndrome, which is associated with insulin-resistant diabetes. We here describe four Japanese individuals from three families with SHORT syndrome who harbor either a common or a previously unknown mutation in PIK3R1 as well as provide an in silico functional analysis of the mutant proteins.
Materials And Methods: Gene sequencing was performed to identify PIK3R1 mutations.
EMBO Mol Med
July 2025
Université Paris Cité, Paris, France.
Mutations in PIK3R1 have recently been identified in patients with overgrowth syndromes and complex vascular malformations. PIK3R1 encodes p85α which acts as the regulatory subunit of the lipid kinase PI3Kα. PIK3R1 mutations result in the excessive activation of the AKT/mTOR pathway.
View Article and Find Full Text PDFMol Divers
February 2025
Bioinformatics Centre, Savitribai Phule Pune University, Pune, 411007, India.
Phosphoinositide 3-kinases (PI3Ks) phosphorylate phosphoinositides on the membrane, which act as secondary signals for various cellular processes. PI3Kα, a heterodimer of the p110α catalytic subunit and the p85α regulatory subunit, is activated by growth factor receptors or mutations. Among these mutations, E545K present in the helical domain is strongly associated with cancer, and is known to disrupt interactions between the regulatory and catalytic subunits, leading to its constitutive activation.
View Article and Find Full Text PDF