Structural Changes during Desmosome Assembly and Maturation

Rose Albert, Reena Beggs, Will Dean, Alexa Mattheyses, PhD. Department of Cell, Developmental and Integrative Biology. University of Alabama at Birmingham. 1900 University Blvd, THT 944, Birmingham, AL, 35294-0006.

Desmosomes are macromolecular cell-cell junctions that resist mechanical stress in epithelia and cardiac muscle. Desmosomal proteins are disrupted in certain cancers, skin blistering diseases, and heart defects such as arrhythmogenic right ventricular cardiomyopathy (ARVC). The nanoscale architecture of desmosomes cannot be studied with conventional, diffraction-limited optical microscopy because desmosomes are structurally complex and only approximately 500 nm in size. Cutting-edge optical approaches such as Fluorescence Polarization Microscopy (FPM) overcome these barriers. FPM provides a quantitative measure of the relative degree of alignment between fluorescently tagged proteins, referred to as the Order Factor. Nascent desmosomes are calcium-dependent and require extracellular calcium to assemble and maintain adhesions and can develop into a calcium-independent, hyper-adhesive state that can resist calcium chelation. A calcium switch model can synchronize these structural changes during desmosome assembly by culturing cells in low-calcium media and then switching to normal calcium media. Previous studies with FPM found that intercellular desmosomal cadherin proteins are ordered in calcium-dependent and calcium-independent desmosomes; however, less is known about how and when this order is acquired during desmosome assembly. This study will utilize FPM to elucidate spatiotemporal dynamics of desmosome assembly through changes in cadherin organization after a calcium switch. I hypothesize cadherin order gradually increases during assembly and maturation and is functionally necessary to acquire adhesion. Observed structural changes can provide insights into the mechanism of desmosomal adhesion and are relevant for understanding desmosome dysfunction in diseased or wounded states.

Additional Abstract Information

Presenter: Rose Albert

Institution: University of Alabama at Birmingham

Type: Poster

Subject: Biology

Status: Approved

Time and Location

Session: Poster 2
Date/Time: Mon 3:00pm-4:00pm
Session Number: 2614