Rogov Vladimir V, Stolz Alexandra, Ravichandran Arvind C, Rios-Szwed Diana O, Suzuki Hironori, Kniss Andreas, Löhr Frank, Wakatsuki Soichi, Dötsch Volker, Dikic Ivan, Dobson Renwick Cj, McEwan David G
Institute of Biophysical Chemistry and Center for Biomolecular Magnetic Resonance, Goethe University, Frankfurt am Main, Germany.
Institute of Biochemistry II, Goethe University School of Medicine, Frankfurt (Main), Germany.
EMBO Rep. 2017 Aug;18(8):1382-1396. doi: 10.15252/embr.201643587. Epub 2017 Jun 27.
Through the canonical LC3 interaction motif (LIR), [W/F/Y]-X-X-[I/L/V], protein complexes are recruited to autophagosomes to perform their functions as either autophagy adaptors or receptors. How these adaptors/receptors selectively interact with either LC3 or GABARAP families remains unclear. Herein, we determine the range of selectivity of 30 known core LIR motifs towards individual LC3s and GABARAPs. From these, we define a ABARAP nteraction otif (GIM) sequence ([W/F]-[V/I]-X-V) that the adaptor protein PLEKHM1 tightly conforms to. Using biophysical and structural approaches, we show that the PLEKHM1-LIR is indeed 11-fold more specific for GABARAP than LC3B. Selective mutation of the X and X positions either completely abolished the interaction with all LC3 and GABARAPs or increased PLEKHM1-GIM selectivity 20-fold towards LC3B. Finally, we show that conversion of p62/SQSTM1, FUNDC1 and FIP200 LIRs into our newly defined GIM, by introducing two valine residues, enhances their interaction with endogenous GABARAP over LC3B. The identification of a GABARAP-specific interaction motif will aid the identification and characterization of the expanding array of autophagy receptor and adaptor proteins and their functions.
通过典型的LC3相互作用基序（LIR），即[W/F/Y]-X-X-[I/L/V]，蛋白质复合物被招募到自噬体上，作为自噬衔接蛋白或受体发挥功能。这些衔接蛋白/受体如何选择性地与LC3或GABARAP家族相互作用仍不清楚。在此，我们确定了30个已知的核心LIR基序对单个LC3和GABARAP的选择性范围。从中，我们定义了一个衔接蛋白PLEKHM1紧密符合的GABARAP相互作用基序（GIM）序列（[W/F]-[V/I]-X-V）。使用生物物理和结构方法，我们表明PLEKHM1-LIR对GABARAP的特异性确实比对LC3B高11倍。X和X位置的选择性突变要么完全消除了与所有LC3和GABARAP的相互作用，要么使PLEKHM1-GIM对LC3B的选择性提高了20倍。最后，我们表明，通过引入两个缬氨酸残基，将p62/SQSTM1、FUNDC1和FIP200的LIR转化为我们新定义的GIM，可增强它们与内源性GABARAP而非LC3B的相互作用。鉴定出一个GABARAP特异性相互作用基序将有助于鉴定和表征不断增加的自噬受体和衔接蛋白阵列及其功能。
