A C-terminal amphipathic helix is necessary for the in vivo tubule-shaping function of a plant reticulon

作者：Breeze Emily; Dzimitrowicz Natasha; Kriechbaumer Verena; Brooks Rhiannon; Botchway Stanley W; Brady Jacob P; Hawes Chris; Dixon Ann M; Schnell Jason R; Fricker Mark D; Frigerio Lorenzo^*

来源：Proceedings of the National Academy of Sciences, 2016, 113(39): 10902-10907.

DOI：10.1073/pnas.1605434113

• plant
• endoplasmic reticulum
• reticulon
• amphipathic helix
• membrane curvature

Reticulons (RTNs) are a class of endoplasmic reticulum (ER) membrane proteins that are capable of maintaining high membrane curvature, thus helping shape the ER membrane into tubules. The mechanism of action of RTNs is hypothesized to be a combination of wedging, resulting from the transmembrane topology of their conserved reticulon homology domain, and scaffolding, arising from the ability of RTNs to form low-mobility homo-oligomers within the membrane. We studied the plant RTN isoform RTN13, which has previously been shown to locate to ER tubules and the edges of ER cisternae and to induce constrictions in ER tubules when overexpressed, and identified a region in the C terminus containing a putative amphipathic helix (APH). Here we show that deletion of this region or disruption of the hydrophobic face of the predicted helix abolishes the ability of RTN13 to induce constrictions of ER tubules in vivo. These mutants, however, still retain their ability to interact and form low-mobility homo-oligomers in the ER membrane. Hence, our evidence indicates that the conserved APH is a key structural feature for RTN13 function in vivo, and we propose that RTN, like other membrane morphogens, rely on APHs for their function.

• 出版日期2016-9-27