TY - JOUR
T1 - The importance of n186 in the alpha-1-antitrypsin shutter region is revealed by the novel bologna deficiency variant
AU - Ronzoni, Riccardo
AU - Ferrarotti, Ilaria
AU - D’acunto, Emanuela
AU - Balderacchi, Alice M.
AU - Ottaviani, Stefania
AU - Lomas, David A.
AU - Irving, James A.
AU - Miranda, Elena
AU - Fra, Annamaria
N1 - Funding Information:
R.R. was supported by a post-doctoral research grant from Alpha-1 Foundation (USA, grant 615837); E.M. was funded by the Alpha-1 Foundation (USA, Pilot & Feasibility grant 497841) and the Italian Pasteur Institute?Cenci Bolognetti Foundation (under 45 grant, call 2018, Italy); A.F. received support from the Italian Association ?1AT; D.A.L. and J.A.I. are supported by Medical Research Council (UK) N024842/1 and D.A.L. is supported by the National Institute for Health Research (NIHR) University College London Hospitals (UCLH) Biomedical Research Centre. D.A.L. is an NIHR Senior Investigator.
Funding Information:
Funding: R.R. was supported by a post-doctoral research grant from Alpha-1 Foundation (USA, grant 615837); E.M. was funded by the Alpha-1 Foundation (USA, Pilot & Feasibility grant 497841) and the Italian Pasteur Institute—Cenci Bolognetti Foundation (under 45 grant, call 2018, Italy); A.F. received support from the Italian Association α1AT; D.A.L. and J.A.I. are supported by Medical Research Council (UK) N024842/1 and D.A.L. is supported by the National Institute for Health Research (NIHR) University College London Hospitals (UCLH) Biomedical Research Centre. D.A.L. is an NIHR Senior Investigator.
Publisher Copyright:
© 2021 by the authors. Licensee MDPI, Basel, Switzerland.
PY - 2021/6/1
Y1 - 2021/6/1
N2 - Alpha-1-antitrypsin (AAT) deficiency causes pulmonary disease due to decreased levels of circulating AAT and consequently unbalanced protease activity in the lungs. Deposition of specific AAT variants, such as the common Z AAT, within hepatocytes may also result in liver disease. These deposits are comprised of ordered polymers of AAT formed by an inter-molecular domain swap. The discovery and characterization of rare variants of AAT and other serpins have historically played a crucial role in the dissection of the structural mechanisms leading to AAT polymer formation. Here, we report a severely deficient shutter region variant, Bologna AAT (N186Y), which was identified in five unrelated subjects with different geographical origins. We characterized the new variant by expression in cellular models in comparison with known polymerogenic AAT variants. Bologna AAT showed secretion deficiency and intracellular accumulation as detergent-insoluble polymers. Extracellular polymers were detected in both the culture media of cells expressing Bologna AAT and in the plasma of a patient homozygous for this variant. Structural modelling revealed that the mutation disrupts the hydrogen bonding network in the AAT shutter region. These data support a crucial coordinating role for asparagine 186 and the importance of this network in promoting formation of the native structure.
AB - Alpha-1-antitrypsin (AAT) deficiency causes pulmonary disease due to decreased levels of circulating AAT and consequently unbalanced protease activity in the lungs. Deposition of specific AAT variants, such as the common Z AAT, within hepatocytes may also result in liver disease. These deposits are comprised of ordered polymers of AAT formed by an inter-molecular domain swap. The discovery and characterization of rare variants of AAT and other serpins have historically played a crucial role in the dissection of the structural mechanisms leading to AAT polymer formation. Here, we report a severely deficient shutter region variant, Bologna AAT (N186Y), which was identified in five unrelated subjects with different geographical origins. We characterized the new variant by expression in cellular models in comparison with known polymerogenic AAT variants. Bologna AAT showed secretion deficiency and intracellular accumulation as detergent-insoluble polymers. Extracellular polymers were detected in both the culture media of cells expressing Bologna AAT and in the plasma of a patient homozygous for this variant. Structural modelling revealed that the mutation disrupts the hydrogen bonding network in the AAT shutter region. These data support a crucial coordinating role for asparagine 186 and the importance of this network in promoting formation of the native structure.
KW - Alpha-1-antitrypsin deficiency
KW - Endoplasmic reticulum
KW - Liver storage disease
KW - Protein aggregation
KW - SERPINA1 alleles
KW - Serpinopathies
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U2 - 10.3390/ijms22115668
DO - 10.3390/ijms22115668
M3 - Article
AN - SCOPUS:85106430982
VL - 22
JO - International Journal of Molecular Sciences
JF - International Journal of Molecular Sciences
SN - 1661-6596
IS - 11
M1 - 5668
ER -