Biology subjects

Haque, R. U.

Publications and source records attributed to Haque, R. U..

3 recordsLinked to original sources

bioRxiv2023

CryoEM reveals the structure of an archaeal pilus involved in twitching motility

Amongst the major archaeal filament types, several have been shown to closely resemble bacterial homologues of the Type IV pili (T4P). Within Sulfolobales, member species encode for three types of T4P, namely the archaellum, the UV-inducible pilus (Uvp) and the archaeal adhesive pilus (Aap). Whereas the archaellum functions primarily in swimming motility, and the Uvp in UV-induced cell aggregation and DNA-exchange, the Aap plays an important role in adhesion and twitching motility. All previously solved Aap appear to have almost identical helical structures. Here, we present a cryoEM structure of the Aap of the archaeal model organism Sulfolobus acidocaldarius. We identify the component subunit as AapB and find that while its structure follows the canonical T4P blueprint, it adopts three distinct conformations within the pilus. The tri-conformer Aap structure that we describe challenges our current understanding of pilus structure and sheds new light on the principles of twitching motility.

microbiology↗

bioRxiv2022

Unbiased Classification of the Human Brain Proteome Resolves Distinct Clinical and Pathophysiological Subtypes of Cognitive Impairment

The hallmark amyloid-{beta} and tau deposition of Alzheimers disease (AD) represents only a fraction of its diverse pathophysiology. Molecular subtyping using large-scale -omic strategies can help resolve this biological heterogeneity. Using quantitative mass spectrometry, we measured ~8,000 proteins across >600 dorsolateral prefrontal cortex tissues from Religious Orders Study and Rush Memory and Aging Project participants with clinical diagnoses of no cognitive impairment, mild cognitive impairment (MCI), and AD dementia. Unbiased classification of MCI and AD cases based on individual proteomic profiles resolved three classes with expression differences across numerous cell types and biological ontologies. Two classes displayed molecular signatures atypical of those previously observed in AD neurodegeneration, such as elevated synaptic and decreased inflammatory markers. In one class, these atypical proteomic features were associated with clinical and pathological hallmarks of cognitive resilience. These results promise to better define disease heterogeneity within AD and meaningfully impact its diagnostic and therapeutic precision.

neuroscience↗

bioRxiv2022

Donor strand complementation, isopeptide bonds and glycosylation stabilise highly resilient archaeal thread filaments

Pili are ubiquitous filamentous surface extensions that play crucial roles for bacterial and archaeal cellular processes such as adhesion, biofilm formation, motility, cell-cell communication, DNA uptake and horizontal gene transfer to name a few. Here we report on the discovery and structure of the archaeal thread - a remarkably stable archaeal pilus that belongs to a so-far largely unknown class of protein filaments. We find that the filament is highly glycosylated and interconnected via donor strand complementation, as well as isopeptide bonds, reminiscent of bacterial type I pili. Despite striking structural similarity with bacterial type-1 pili, archaeal threads appear to have evolved independently and are likely assembled by a markedly distinct mechanism.

microbiology↗