bi8b00726_si_001.pdf (1.25 MB)
MIEF1 Microprotein Regulates Mitochondrial Translation
journal contribution
posted on 2018-09-14, 13:40 authored by Annie Rathore, Qian Chu, Dan Tan, Thomas F. Martinez, Cynthia J. Donaldson, Jolene K. Diedrich, John R. Yates, Alan SaghatelianRecent
technological advances led to the discovery of hundreds
to thousands of peptides and small proteins (microproteins) encoded
by small open reading frames (smORFs). Characterization of new microproteins
demonstrates their role in fundamental biological processes and highlights
the value in discovering and characterizing more microproteins. The
elucidation of microprotein–protein interactions (MPIs) is
useful for determining the biochemical and cellular roles of microproteins.
In this study, we characterize the protein interaction partners of
mitochondrial elongation factor 1 microprotein (MIEF1-MP) using a
proximity labeling strategy that relies on APEX2. MIEF1-MP localizes
to the mitochondrial matrix where it interacts with the mitochondrial
ribosome (mitoribosome). Functional studies demonstrate that MIEF1-MP
regulates mitochondrial translation via its binding to the mitoribosome.
Loss of MIEF1-MP decreases the mitochondrial translation rate, while
an elevated level of MIEF1-MP increases the translation rate. The
identification of MIEF1-MP reveals a new gene involved in this process.