Biology subjects

Williams, S. E.

Publications and source records attributed to Williams, S. E..

2 recordsLinked to original sources

bioRxiv2019

A schizophrenia risk locus alters brain metal transport and plasma glycosylation

A common missense variant in SLC39A8 is convincingly associated with schizophrenia and several additional phenotypes. Homozygous loss-of-function mutations in SLC39A8 result in undetectable serum manganese (Mn) and a Congenital Disorder of Glycosylation (CDG) due to the exquisite sensitivity of glycosyltransferases to Mn concentration. Here, we identified several Mn-related changes in human carriers of the common SLC39A8 missense allele. Analysis of structural brain MRI scans showed a dose-dependent change in the ratio of T2w to T1w signal in several regions. Comprehensive trace element analysis confirmed a specific reduction of only serum Mn, and plasma protein N-glycome profiling revealed reduced complexity and branching. N-glycome profiling from two individuals with SLC39A8-CDG showed similar but more severe alterations in branching that improved with Mn supplementation, suggesting that the common variant exists on a spectrum of hypofunction with potential for reversibility. Characterizing the functional impact of this variant will enhance our understanding of schizophrenia pathogenesis and identify novel therapeutic targets and biomarkers of disease. SummaryA common variant in the manganese transporter SLC39A8 is associated with numerous phenotypes including schizophrenia. Mealer et. al. presents an in-depth analysis of brain MRI and plasma glycomics in human carriers of the common variant, identifying several manganese-related changes with potential for diagnostic and therapeutic biomarker development.

biochemistry↗

bioRxiv2019

Telophase correction refines division orientation in stratified epithelia

During organogenesis, precise control of spindle orientation ensures a proper balance of proliferation and differentiation. In the developing murine epidermis, planar and perpendicular divisions yield symmetric and asymmetric fate outcomes, respectively. Classically, division axis specification involves centrosome migration and spindle rotation, events that occur early in mitosis. Here, we identify a previously uncharacterized orientation mechanism that occurs during telophase, correcting erroneous oblique orientations that unexpectedly persist into anaphase. The directionality of reorientation--towards either planar or perpendicular--correlates with the maintenance or loss of basal contact by the apical daughter. While the conserved scaffolding protein Pins/LGN is believed to function primarily through initial spindle positioning, we now show it also functions actively during telophase to reorient oblique divisions toward perpendicular. The ability to undergo telophase correction is also critically dependent upon an LGN-independent pathway involving the tension-sensitive adherens junction proteins vinculin, a-catenin and afadin, and correction directionality is influenced by local cell density. Failure of this reorientation mechanism impacts tissue architecture, as excessive oblique divisions induce precocious differentiation. The division orientation plasticity provided by telophase correction may provide a means for progenitors to dynamically respond to extrinsic cues provided by neighboring cells in order to adapt to local tissue needs.

cell biology↗