{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"institution":[{"name":"bioRxiv"}],"indexed":{"date-parts":[[2026,1,15]],"date-time":"2026-01-15T19:48:56Z","timestamp":1768506536618,"version":"3.49.0"},"posted":{"date-parts":[[2023,8,17]]},"group-title":"Biophysics","reference-count":66,"publisher":"openRxiv","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"accepted":{"date-parts":[[2023,8,17]]},"abstract":"<jats:title>ABSTRACT<\/jats:title>\n                <jats:p>Small heat shock proteins (sHSPs) are ATP-independent chaperones vital to cellular proteostasis, preventing protein aggregation events linked to various human diseases including cataract. The \u03b1-crystallins, \u03b1A-crystallin (\u03b1Ac) and \u03b1B-crystallin (\u03b1Bc), represent archetypal sHSPs that exhibit complex polydispersed oligomeric assemblies and rapid subunit exchange dynamics. Yet, our understanding of how this plasticity contributes to chaperone function remains poorly understood. This study investigates structural changes in \u03b1Ac and \u03b1Bc during client sequestration under varying degree of chaperone saturation. Using biochemical and biophysical analyses combined with single-particle electron microscopy (EM), we examined \u03b1Ac and \u03b1Bc in their apo-states and at various stages of client-induced co-aggregation, using lysozyme as a model client. Quantitative single-particle analysis unveiled a continuous spectrum of oligomeric states formed during the co-aggregation process, marked by significant client-triggered expansion and quasi-ordered elongation of the sHSP scaffold. These structural modifications culminated in an apparent amorphous collapse of chaperone-client complexes, resulting in the creation of co-aggregates capable of scattering visible light. Intriguingly, these co-aggregates maintain internal morphological features of highly elongated sHSP scaffolding with striking resemblance to polymeric \u03b1-crystallin species isolated from aged lens tissue. This mechanism appears consistent across both \u03b1Ac and \u03b1Bc, albeit with varying degrees of susceptibility to client-induced co-aggregation. Importantly, our findings suggest that client-induced co-aggregation follows a distinctive mechanistic and quasi-ordered trajectory, distinct from a purely amorphous process. These insights reshape our understanding of the physiological and pathophysiological co-aggregation processes of sHSPs, carrying potential implications for a pathway toward cataract formation.<\/jats:p>","DOI":"10.1101\/2023.08.15.553435","type":"posted-content","created":{"date-parts":[[2023,8,17]],"date-time":"2023-08-17T16:40:15Z","timestamp":1692290415000},"source":"Crossref","is-referenced-by-count":1,"title":["The \u03b1-crystallin chaperones undergo a quasi-ordered co-aggregation process in response to saturating client interaction"],"prefix":"10.64898","author":[{"given":"Adam P.","family":"Miller","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Susan E.","family":"O\u2019Neill","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7906-6699","authenticated-orcid":false,"given":"Kirsten J.","family":"Lampi","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5276-7690","authenticated-orcid":false,"given":"Steve L.","family":"Reichow","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"54368","reference":[{"key":"2023082110050613000_2023.08.15.553435v1.1","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.89.21.10449"},{"key":"2023082110050613000_2023.08.15.553435v1.2","doi-asserted-by":"publisher","DOI":"10.1016\/0014-5793(85)81102-9"},{"key":"2023082110050613000_2023.08.15.553435v1.3","doi-asserted-by":"publisher","DOI":"10.1016\/j.biocel.2012.06.005"},{"key":"2023082110050613000_2023.08.15.553435v1.4","doi-asserted-by":"publisher","DOI":"10.1379\/1466-1268(2003)8<53:THGECS>2.0.CO;2"},{"key":"2023082110050613000_2023.08.15.553435v1.5","doi-asserted-by":"publisher","DOI":"10.1016\/S0014-4835(02)00278-6"},{"key":"2023082110050613000_2023.08.15.553435v1.6","doi-asserted-by":"publisher","DOI":"10.1016\/j.pbiomolbio.2014.02.006"},{"key":"2023082110050613000_2023.08.15.553435v1.7","doi-asserted-by":"publisher","DOI":"10.1016\/j.bbapap.2014.12.019"},{"key":"2023082110050613000_2023.08.15.553435v1.8","doi-asserted-by":"publisher","DOI":"10.1007\/s00018-008-8327-4"},{"key":"2023082110050613000_2023.08.15.553435v1.9","doi-asserted-by":"publisher","DOI":"10.1074\/jbc.REV118.002809"},{"key":"2023082110050613000_2023.08.15.553435v1.10","doi-asserted-by":"publisher","DOI":"10.1006\/jmbi.2000.3657"},{"key":"2023082110050613000_2023.08.15.553435v1.11","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.1932958100"},{"key":"2023082110050613000_2023.08.15.553435v1.12","doi-asserted-by":"crossref","first-page":"29208","DOI":"10.1038\/srep29208","article-title":"New insight into the dynamical system of alphaB-crystallin oligomers","volume":"6","year":"2016","journal-title":"Sci Rep"},{"key":"2023082110050613000_2023.08.15.553435v1.13","doi-asserted-by":"publisher","DOI":"10.1074\/jbc.274.14.9378"},{"key":"2023082110050613000_2023.08.15.553435v1.14","doi-asserted-by":"publisher","DOI":"10.1074\/jbc.274.21.14867"},{"key":"2023082110050613000_2023.08.15.553435v1.15","doi-asserted-by":"crossref","first-page":"e2213765120","DOI":"10.1073\/pnas.2213765120","article-title":"Disordered region encodes alpha-crystallin chaperone activity toward lens client gammaD-crystallin","volume":"120","year":"2023","journal-title":"Proc Natl Acad Sci U S A"},{"key":"2023082110050613000_2023.08.15.553435v1.16","doi-asserted-by":"publisher","DOI":"10.1007\/s12192-020-01092-2"},{"key":"2023082110050613000_2023.08.15.553435v1.17","doi-asserted-by":"crossref","unstructured":"Clouser AF , Baughman HE , Basanta B , Guttman M , Nath A , Klevit RE . 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