Identification of SERCA binding to FNIP1. (A) Interacting proteins of FNIP1 identified by mass spectrometry. Left: Strategy for identification of FNIP1 binding protein. Whole gastrocnemius muscle lysates from Fnip1^Tg mice were used for IP and MS studies. Right: Interacting proteins of FNIP1 (yellow) identified by mass spectrometry. The orange dots are the ER Ca²⁺-ATPase SERCA2. The blue dots are the known binding partner of FNIP1 (FLCN, AMPKγ1, and AMPKβ2). (B) List of the top 10 FNIP1 binding proteins ranked by the normalized spectral abundance factor value. (C) Flag-FNIP1 is colocalized with the ER marker GFP-MANII in HEK293T cells. Nuclei were stained by DAPI. Scale bar: 100 μm. Data are representative of at least three independent experiments (C).