https://www.selleckchem.com/products/ginkgolic-acid-s9432.html The endoplasmic reticulum (ER), with its expansive membranous system and a vast network of chaperones, enzymes, sensors, and ion channels, orchestrates diverse cellular functions, ranging from protein synthesis, folding, secretion, and degradation to lipid biogenesis and calcium homeostasis. Strikingly, some of the functions of the ER are exploited by viruses to promote their life cycles. During entry, viruses must penetrate a host membrane and reach an intracellular destination to express and replicate their genomes. These events lead to the assembly of new viral progenies that exit the host cell, thereby initiating further rounds of infection. In this review, we highlight how three distinct viruses - polyomavirus, flavivirus, and coronavirus - co-opt key functions of the ER to cause infection. We anticipate that illuminating this virus-ER interplay will provide rational therapeutic approaches to combat the virus-induced diseases.The role of miR-21 in the pathogenesis of various liver diseases, together with the possibility of detecting microRNA in the circulation, makes miR-21 a potential biomarker for noninvasive detection. In this review, we summarize the potential utility of extracellular miR-21 in the clinical management of hepatic disease patients and compared it with the current clinical practice. MiR-21 shows screening and prognostic value for liver cancer. In liver cirrhosis, miR-21 may serve as a biomarker for the differentiating diagnosis and prognosis. MiR-21 is also a potential biomarker for the severity of hepatitis. We elucidate the disease condition under which miR-21 testing can reach the expected performance. Though miR-21 is a key regulator of liver diseases, microRNAs coordinate with each other in the complex regulatory network. As a result, the performance of miR-21 is better when combined with other microRNAs or classical biomarkers under certain clinical circumstances. Enhancers a