Biology subjects

Wenzel, W.

Publications and source records attributed to Wenzel, W..

2 recordsLinked to original sources

bioRxiv2025

Structural dynamics in the CENP-A nucleosome impacted by protein-protein interactions with centromere protein N

Noncanonical nucleosomes at the centromere contain the histone variant CENP-A, playing a crucial role in chromosome segregation. CENP-A is highly regulated and its centromeric organization is partially regulated by the centromere protein N (CENP-N). Despite its importance, the protein-protein interactions within the complex formed between CENP-A nucleosomes and CENP-N remain poorly understood at a molecular level. Here, we employ the SIRAH coarse-grained molecular dynamics (MD) simulations to investigate the binding interface and structural rearrangements of proteins in the CENP-A nucleosome complexed with CENP-N. We aim to assess the stability of the CENP-A nucleosome and the change in its plasticity upon the CENP-N binding. By the set of {micro}s-long MDs, we reveal enhanced flexibility in the N-terminal region of CENP-A and stabilization of its RG loop in the complex with CENP-N. This is demonstrated to have rather minor effects on the overall stability of the nucleosome and changing its compactness. Nevertheless, the data suggest the binding of CENP-N allosterically changes the conformational states of CENP-A and impacts its interactions with other proteins in the histone core. A distance-based contact map analysis further elucidates key residues mediating the interaction between CENP-A and CENP-N, while umbrella sampling simulations quantify their binding free energy, which remains challenging to measure experimentally.

biophysics↗

bioRxiv2019

Deficiency in the endocytic adaptor protein PHETA1/2 impairs renal and craniofacial development

A critical barrier in the treatment of endosomal and lysosomal diseases is the lack of understanding of the in vivo functions of the putative causative genes. We addressed this by investigating a key pair of endocytic adaptor proteins, PH domain containing endocytic trafficking adaptor 1 and 2 (PHETA1/2, also known as FAM109A/B, Ses1/2, IPIP27A/B), which interact with the protein product of OCRL, the causative gene for Lowe syndrome. Here we conducted the first study of PHETA1/2 in vivo, utilizing the zebrafish system. We found that impairment of both zebrafish orthologs, pheta1 and pheta2, disrupted endocytosis and ciliogenesis. In addition, pheta1/2 mutant animals exhibited reduced jaw size and delayed chondrocyte maturation, indicating a role in craniofacial development. Deficiency of pheta1/2 resulted in dysregulation of cathepsin K, which led to an increased abundance of type II collagen in craniofacial cartilages. The abnormal renal and craniofacial phenotypes in the pheta1/2 mutant animals were consistent with the clinical presentations of a patient with a de novo arginine (R) to cysteine (C) variant (R6C) of PHETA1. Expressing the patient-specific variant in zebrafish exacerbated craniofacial deficits, suggesting that the R6C allele acts in a dominant-negative manner. Together, these results provide insights into the in vivo roles of PHETA1/2 and suggest that the R6C variant is contributory to the pathogenesis of disease in the patient.

developmental biology↗