Differential gradients of interaction affinities drive efficient targeting and recycling in the GET pathway

摘要: Efficient and accurate localization of membrane proteins requires a complex cascade interactions between protein machineries. This requirement is exemplified in the guided entry tail-anchored (TA) (GET) pathway, where central targeting factor Get3 must sequentially interact with three distinct binding partners to ensure delivery TA endoplasmic reticulum (ER) membrane. To understand molecular principles that provide vectorial driving force these interactions, we developed quantitative fluorescence assays monitor Get3–effector at each stage targeting. We show nucleotide substrate generate differential gradients interaction energies drive ordered successive effectors. These data also more details on how captured disassembled by ER receptor reveal previously unidentified role for Get4/5 recycling from end reaction. results general insights into cascades are coupled energy inputs biological systems.