A combined immunodeficiency with severe infections, inflammation, and allergy caused by ARPC1B deficiency

Abstract

A combined immunodeficiency with severe infections, inflammation, and allergy caused by ARPC1B deficiency To the Editor:Recently, a novel syndrome of combined immunodeficiency, allergy, and ''auto''inflammation caused by mutations in the ARPC1B gene has been reported. [1][2][3][4] Analysis of patient-derived

Cryo-EM of human Arp2/3 complexes provides structural insights into actin nucleation modulation by ARPC5 isoforms

“…Recent work has shown that the ARPC1 and ARPC5 isoforms differentially affect the actin nucleating properties of the Arp2/3 complex and the stability of the branched filament networks it generates (Abella et al, 2016). Furthermore, tissue-specific expression patterns of subunit isoforms, together with isoform-specific susceptibility to disease-causing point mutations, point to distinct physiological roles for particular Arp2/3 isoforms in nuclei positioning in skeletal muscle (Roman et al, 2017), as well as cytotoxic T lymphocyte maintenance and activity (Brigida et al, 2018;Kuijpers et al, 2017;Randzavola et al, 2019;Somech et al, 2017;Volpi et al, 2019;Roman et al, 2017;Kahr et al, 2017).…”

Higher Incidence of B Cell Malignancies in Primary Immunodeficiencies: A Combination of Intrinsic Genomic Instability and Exocytosis Defects at the Immunological Synapse

“…Therefore, among all the treatments options currently available for PID patients, hematopoietic stem cell transplantation (HSCT) is the most curative and reliable one. Multiple studies have reported significant efficacy of HSCT in different PID associated with synaptic defects ( 92 , 201 , 298 – 305 ). However, HSCT is a heavy surgical procedure that requires prior immunosuppressive conditioning.…”

Cryo-EM of human Arp2/3 complexes provides structural insights into actin nucleation modulation by ARPC5 isoforms

“…Loss-of-function mutations of ARPC1B give rise to multisystem inflammatory and immunodeficiency diseases (Brigida et al, 2018;Kahr et al, 2017;Kuijpers et al, 2017;Randzavola et al, 2019;Somech et al, 2017;Volpi et al, 2019), similar to Wiskott-Aldrich syndrome that is caused by mutations in the Arp2/3 activator WASP (Bosticardo et al, 2009). While some patients carry mutations causing premature protein termination and total loss of ARPC1B protein, four point mutations -W104S, A105V, V208F and A238T -have also been observed in patients (Brigida et al, 2018;Kahr et al, 2017;Volpi et al, 2019) (Figure 2A, right, purple spheres). W104, A105 and V208 are located in the core of the ARPC1B subunit β-propeller fold and this mutation likely destabilizes its tertiary fold, causing severely reduced protein levels in patients (Kahr et al, 2017).…”

“…Recent work has shown that the ARPC1 and ARPC5 isoforms differentially affect the actin nucleating properties of the Arp2/3 complex and the stability of the branched filament networks it generates (Abella et al, 2016). Furthermore, tissue-specific expression patterns of subunit isoforms, together with isoformspecific susceptibility to disease-causing point mutations, point to distinct physiological roles for particular Arp2/3 isoforms including cytotoxic T lymphocyte maintenance and activity (Brigida et al, 2018;Kahr et al, 2017;Kuijpers et al, 2017;Randzavola et al, 2019;Roman et al, 2017;Somech et al, 2017;Volpi et al, 2019).…”