Drug eruption caused by azathioprine: Value of using the drug-induced lymphocytes stimulation test for diagnosis
JOURNAL OF DERMATOLOGY
Authors: Mori, H; Yamanaka, K; Kaketa, M; Tamada, K; Hakamada, A; Isoda, K; Yamanishi, K; Mizutani, H
Abstract
Azathioprine (AZA) is an immunosuppressant commonly used for organ transplantation and autoimmune diseases. Allergic side effects of AZA are rare, and reported allergic skin eruptions from AZA are very limited in Japan. We report AZA-induced drug eruption that developed in two cases of systemic scleroderma with polymyositis. One case presented with Stevens-Johnson syndrome, and the other had systemic papular erythema. The stimulation indices of the drug-induced lymphocyte stimulation test (DLST) for AZA in these two patients were as high as 2,180% and 430%, respectively, but those of healthy volunteers were under 120% without nonspecific suppression of lymphocyte proliferation. Other drugs used simultaneously were ruled out by patch and challenge tests. The challenge test for Stevens-Johnson syndrome type drug allergy is very risky. DLST is a good diagnostic tool for AZA allergy, especially for severe drug allergy cases.
Comparative Analysis of Mitochondrial N-Termini from Mouse, Human, and Yeast
MOLECULAR & CELLULAR PROTEOMICS
Authors: Calvo, Sarah E.; Julien, Olivier; Clauser, Karl R.; Shen, Hongying; Kamer, Kimberli J.; Wells, James A.; Mootha, Vamsi K.
Abstract
The majority of mitochondrial proteins are encoded in the nuclear genome, translated in the cytoplasm, and directed to the mitochondria by an N-terminal presequence that is cleaved upon import. Recently, N-proteome catalogs have been generated for mitochondria from yeast and from human U937 cells. Here, we applied the subtiligase method to determine N-termini for 327 proteins in mitochondria isolated from mouse liver and kidney. Comparative analysis between mitochondrial N-termini from mouse, human, and yeast proteins shows that whereas presequences are poorly conserved at the sequence level, other presequence properties are extremely conserved, including a length of approximate to 20-60 amino acids, a net charge between +3 to +6, and the presence of stabilizing amino acids at the N-terminus of mature proteins that follow the N-end rule from bacteria. As in yeast, approximate to 80% of mouse presequence cleavage sites match canonical motifs for three mitochondrial peptidases (MPP, Icp55, and Oct1), whereas the remainder do not match any known peptidase motifs. We show that mature mitochondrial proteins often exist with a spectrum of N-termini, consistent with a model of multiple cleavage events by MPP and Icp55. In addition to analysis of canonical targeting presequences, our N-terminal dataset allows the exploration of other cleavage events and provides support for polypeptide cleavage into two distinct enzymes (Hsd17b4), protein cleavages key for signaling (Oma1, Opa1, Htra2, Mavs, and Bcs2l13), and in several cases suggests novel protein isoforms (Scp2, Acadm, Adck3, Hsdl2, Dlst, and Ogdh). We present an integrated catalog of mammalian mitochondrial N-termini that can be used as a community resource to investigate individual proteins, to elucidate mechanisms of mammalian mitochondrial processing, and to allow researchers to engineer tags distally to the presequence cleavage.