WWP1 E3 ligase at the crossroads of health and disease.

The E3 ubiquitin ligase WWP1 (WW Domain-containing E3 Ubiquitin Protein Ligase 1) is a member of the HECT (Homologous to the E6-associated protein Carboxyl Terminus) E3 ligase family. It is conserved across several species and plays crucial roles in various physiological processes, including development, cell growth and proliferation, apoptosis, and differentiation. It exerts its functions through ubiquitination or protein-protein interaction with PPXY-containing proteins. WWP1 plays a role in several human diseases, including cardiac conditions, neurodevelopmental, age-associated osteogenic disorders, infectious diseases, and cancers. In solid tumors, WWP1 plays a dual role as both an oncogene and a tumor suppressor, whereas in hematological malignancies such as AML, it is identified as a dedicated oncogene. Importantly, WWP1 inhibition using small molecule inhibitors such as Indole-3-Carbinol (I3C) and Bortezomib or siRNAs leads to significant suppression of cancer growth and healing of bone fractures, suggesting that WWP1 might serve as a potential therapeutic target for several diseases. In this review, we discuss the evolutionary perspective, structure, and functions of WWP1 and its multilevel regulation by various regulators. We also examine its emerging roles in cancer progression and its therapeutic potential. Finally, we highlight WWP1's role in normal physiology, contribution to pathological conditions, and therapeutic potential for cancer and other diseases.

AMPK-induced novel phosphorylation of RUNX1 inhibits STAT3 activation and overcome imatinib resistance in chronic myelogenous leukemia (CML) subjects.

Imatinib resistance remains an unresolved problem in CML disease. Activation of JAK2/STAT3 pathway and increased expression of RUNX1 have become one reason for development of imatinib resistance in CML subjects. Metformin has gained attention as an antileukemic drug in recent times. However, the molecular mechanism remains elusive. The present study shows that RUNX1 is a novel substrate of AMP-activated kinase (AMPK), where AMPK phosphorylates RUNX1 at Ser 94 position. Activation of AMPK by metformin could lead to increased cytoplasmic retention of RUNX1 due to Ser 94 phosphorylation. RUNX1 Ser 94 phosphorylation resulted in increased interaction with STAT3, which was reflected in reduced transcriptional activity of both RUNX1 and STAT3 due to their cytoplasmic retention. The reduced transcriptional activity of STAT3 and RUNX1 resulted in the down-regulation of their signaling targets involved in proliferation and anti-apoptosis. Our cell proliferation assays using in vitro resistant cell line models and PBMCs isolated from CML clinical patients and normal subjects demonstrate that metformin treatment resulted in reduced growth and improved imatinib sensitivity of resistant subjects.

Ectopic expression of Arabidopsis Target of Rapamycin (AtTOR) improves water-use efficiency and yield potential in rice.

The target of Rapamycin (TOR) present in all eukaryotes is a multifunctional protein, regulating growth, development, protein translation, ribosome biogenesis, nutrient, and energy signaling. In the present study, ectopic expression of TOR gene of Arabidopsis thaliana in a widely cultivated indica rice resulted in enhanced plant growth under water-limiting conditions conferring agronomically important water-use efficiency (WUE) trait. The AtTOR high expression lines of rice exhibited profuse tillering, increased panicle length, increased plant height, high photosynthetic efficiency, chlorophyll content and low ∆13C. Δ13C, which is inversely related to high WUE, was as low as 17‰ in two AtTOR high expression lines. These lines were also insensitive to the ABA-mediated inhibition of seed germination. The significant upregulation of 15 stress-specific genes in high expression lines indicates their contribution to abiotic stress tolerance. The constitutive expression of AtTOR is also associated with significant transcriptional upregulation of putative TOR complex-1 components, OsRaptor and OsLST8. Glucose-mediated transcriptional activation of AtTOR gene enhanced lateral root formation. Taken together, our findings indicate that TOR, in addition to its multiple cellular functions, also plays an important role in response to abiotic stress and potentially enhances WUE and yield related attributes.

Mutation spectrum of the CYP1B1 gene in Indian primary congenital glaucoma patients.

PURPOSE: The human Cytochrome P450 gene CYP1B1 has been implicated in primary congenital glaucoma worldwide. The aim of this study was to understand the role of CYP1B1 mutations in causing primary congenital glaucoma in Indian populations. METHODS: The study included 64 new and unrelated cases of primary congenital glaucoma from different ethnic groups of India. Direct sequencing screened the coding and the promoter regions of CYP1B1. RESULTS: Sixteen pathogenic mutations were observed in 24 cases, of which 7 were novel. These included two frameshift mutations leading to deletions of 23 bp (g.3905del23bp) and 2 bp (g.7900-7901delCG) in exons II and III, respectively. Four novel missense mutations viz. A115P, M132R, Q144P, S239R were noted in exon II, and one in exon III (G466D), whose residue is a part of the "signature sequence" (NH2-FXXGXXXCXG-COOH) and is present in all heme binding cytochromes. Overall, CYP1B1 was involved in 37.50% (24/64) cases and homozygosity of the mutant allele was seen in 29.68% (19/64) and compound heterozygosity in 3.12% (2/64) of the cases, respectively. The frequency of CYP1B1 mutations was comparatively lower than Saudi Arabian, Slovakian Gypsys, and Turkish populations, largely due to genetic heterogeneity and ethnic diversities in Indian populations. Genotype-phenotype correlation indicated variable prognosis that could be due to the type of mutation, leading to alteration of CYP1B1 protein. CONCLUSIONS: This study provides a mutation spectrum of CYP1B1 causing primary congenital glaucoma in Indian populations that has implications in devising molecular diagnostics for rapid screening.

Mutation spectrum of FOXC1 and clinical genetic heterogeneity of Axenfeld-Rieger anomaly in India.

PURPOSE: Axenfeld-Rieger anomaly (ARA) is a form of anterior segment dysgenesis of the eye, mainly caused by mutations in the FOXC1 gene. We had earlier reported a novel mutation in the wing region of FOXC1 in an autosomal dominant family. The present study was aimed to identify the spectrum of mutations in the FOXC1 gene in a cohort of Indian ARA patients from different ethnic backgrounds, and to understand its role in the disease pathogenesis. METHODS: Two new autosomal dominant families and seven sporadic cases of ARA from different ethnic backgrounds were screened for mutations by direct sequencing of the coding region of the FOXC1 gene. Another autosomal dominant ARA family that was previously reported by us was also included for comparative analysis of clinical genetic parameters. The segregation of the mutations in the autosomal dominant families was analyzed by haplotype and restriction analysis. Genotype-phenotype correlation were also undertaken to study the role of FOXC1 in phenotypic manifestation in the patient cohort. RESULTS: Three of the nine ARA cases harbored mutations in FOXC1, of which two novel nonsense mutations Q2X and Q123X, resulted in haploinsufficiency of the gene product. The missense mutation (M161K) that we previously reported in an autosomal dominant family was also found in another family. Haplotype analysis of these two families suggested multiple founders in the same ethnic group. The mutations resulted in variable expressions of phenotype among the patients as assessed from their prognosis based on visual outcomes. CONCLUSIONS: Significant genetic heterogeneity of FOXC1 was observed in a multi-ethnic population studied in this region of India resulting in variable ARA phenotypes. The different visual outcome seen in the patients suggest a variable expression of FOXC1 and also provide some insight for understanding the gene functions in this population.