Mattoo lab develops a new cell biology tool called CryoAPEX
Localization of membrane-bound proteins by electron microscopy (EM) has been challenging because current methods of sample processing damage membrane integrity. The Mattoo lab has developed a new EM method, termed CryoAPEX, that couples chemical fixation and high-pressure freezing of cells with peroxidase tagging (APEX) to allow precise localization of membrane proteins in the context of a well preserved sub-cellular architecture. This information can further be used to build a 3D image of the protein inside the cell. Importantly, CryoAPEX can be applied to cells grown in tissue culture, thus making this technique more accessible to the general scientific community.
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Legend for accompanying figure:
A 3D model of the endoplasmic reticulum (in blue) displaying density associated with transiently expressed APEX2-tagged human Fic protein, HYPE/FicD (in gold). The model was generated from an electron tomogram of a cell processed by Cryo-APEX, a technique that allows staining of membrane proteins without damaging membrane ultrastructure. Virtual sections of the tomogram are presented in the background. Cryo-APEX can be widely applied to cells grown in tissue culture.