Nobuo Kanazawa, Hiroaki Hemmi, Noriko Kinjo, Hidenori Ohnishi, Jun Hamazaki, Hiroyuki Mishima, Akira Kinoshita, Tsunehiro Mizushima, Satoru Hamada, Kazuya Hamada, Norio Kawamoto, Saori Kadowaki, Yoshitaka Honda, Kazushi Izawa, Ryuta Nishikomori, Miyuki Tsumura, Yusuke Yamashita, Shinobu Tamura, Takashi Orimo, Toshiya Ozasa, Takashi Kato, Izumi Sasaki, Yuri Fukuda-Ohta, Naoko Wakaki-Nishiyama, Yutaka Inaba, Kayo Kunimoto, Satoshi Okada, Takeshi Taketani, Koichi Nakanishi, Shigeo Murata, Koh-Ichiro Yoshiura, Tsuneyasu Kaisho
Nature communications, 12(1) 6819-6819, Nov 24, 2021 Peer-reviewed
Impaired proteasome activity due to genetic variants of certain subunits might lead to proteasome-associated autoinflammatory syndromes (PRAAS). Here we report a de novo heterozygous missense variant of the PSMB9 proteasome subunit gene in two unrelated Japanese infants resulting in amino acid substitution of the glycine (G) by aspartic acid (D) at position 156 of the encoded protein β1i. In addition to PRAAS-like manifestations, these individuals suffer from pulmonary hypertension and immunodeficiency, which are distinct from typical PRAAS symptoms. The missense variant results in impaired immunoproteasome maturation and activity, yet ubiquitin accumulation is hardly detectable in the patients. A mouse model of the heterozygous human genetic variant (Psmb9G156D/+) recapitulates the proteasome defects and the immunodeficiency phenotype of patients. Structurally, PSMB9 G156D interferes with the β-ring-βring interaction of the wild type protein that is necessary for 20S proteasome formation. We propose the term, proteasome-associated autoinflammatory syndrome with immunodeficiency (PRAAS-ID), to indicate a separate category of autoinflammatory diseases, similar to, but distinct from PRAAS, that describes the patients in this study.