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Transcripts of the KRAS locus are alternatively spliced to generate two proteins, KRAS4A and KRAS4B, which differ in their membrane-targeting sequences. These splice variants have been conserved for more than 450 million years, suggesting non-overlapping functions driven by differential membrane association. Here, we use proximity labeling to map the differential interactomes of the KRAS splice variants. We find 24 and 10 proteins that interact specifically with KRAS4A or KRAS4B, respectively. The KRAS interacting protein most specific to KRAS4A is BIRC6, a large member of the inhibitor of apoptosis protein family unique in possessing E2/E3 ubiquitin ligase activity. We find that this interaction takes place on the Golgi apparatus and results in the mono- and di-ubiquitination of KRAS4A at lysines 128 and 147. Silencing BIRC6 diminishes GTP loading of and growth stimulation by KRAS4A but not KRAS4B. Thus, BIRC6 is a ubiquitin ligase that inhibits apoptosis and also modifies KRAS4A.
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http://dx.doi.org/10.1016/j.celrep.2024.115087 | DOI Listing |
Signal Transduct Target Ther
September 2025
State Key Laboratory of Molecular Oncology & Department of Medical Oncology & Department of Pathology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
Small-cell lung cancer (SCLC), an aggressive neuroendocrine tumor strongly associated with exposure to tobacco carcinogens, is characterized by early dissemination and dismal prognosis with a five-year overall survival of less than 7%. High-frequency gain-of-function mutations in oncogenes are rarely reported, and intratumor heterogeneity (ITH) remains to be determined in SCLC. Here, via multiomics analyses of 314 SCLCs, we found that the ASCL1/MKI67 and ASCL1/CRIP2 clusters accounted for 74.
View Article and Find Full Text PDFAm J Hum Genet
September 2025
Department of Clinical Genetics, Erasmus MC, University Medical Center Rotterdam, PO Box 2040, Rotterdam 3000 CA, the Netherlands.
Microtubule-actin cross-linking factor 1 (MACF1) is a large protein of the spectraplakin family, which is essential for brain development. MACF1 interacts with microtubules through the growth arrest-specific 2 (Gas2)-related (GAR) domain. Heterozygous MACF1 missense variants affecting the zinc-binding residues in this domain result in a distinctive cortical and brain stem malformation.
View Article and Find Full Text PDFNucleic Acids Res
September 2025
Shenzhen Key Laboratory of Cardiovascular Disease, Fuwai Shenzhen Hospital, Chinese Academy of Medical Sciences, Shenzhen 518057, China.
EZH2 catalyzes H3K27me3 and is essential for embryonic development. Although multiple EZH2 variants have been identified, the functional implications and physiological significance of its heterogeneity remain unclear. Here, we revealed that conserved cryptic splice sites generated two EZH2 variants with (EZH2A) or without (EZH2B) a 27-nt region, coding for a 9-aa segment.
View Article and Find Full Text PDFFront Genet
August 2025
Medical School, Kunming University of Science and Technology, The First People's Hospital of Yunnan Province, Kunming, Yunnan, China.
Background: Stickler syndrome (STL) is a group of related connective tissue disorders characterized by heterogeneous clinical presentations with varying degrees of orofacial, ocular, skeletal, and auditory abnormalities. However, this condition is difficult to diagnose on the basis of clinical features because of phenotypic variability. Thus, expanding the variant spectrum of this disease will aid in achieving a firm definitive diagnosis of STL.
View Article and Find Full Text PDFRecursive splice sites are rare motifs postulated to facilitate splicing across massive introns and shape isoform diversity, especially for long, brain-expressed genes. The necessity of this unique mechanism remains unsubstantiated, as does the role of recursive splicing (RS) in human disease. From analyses of rare copy number variants (CNVs) from almost one million individuals, we previously identified large, heterozygous deletions eliminating an RS site (RS1) in the first intron of that conferred substantial risk for attention deficit hyperactivity disorder (ADHD) and other neurobehavioral traits.
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