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. Author manuscript; available in PMC: 2014 Apr 25.
Published in final edited form as: Nat Commun. 2011 Jan 11;2:153. doi: 10.1038/ncomms1153

Figure 1. Identification of CATSPERδ encoded by Tmem146 as an auxiliary subunit of native CATSPER channels.

Figure 1

(a) Purified CATSPER1 complex (α-CATSPER1) separated by SDS-PAGE and stained with Coomassie blue. Rabbit IgG column eluate serves as control (IgG). Numbered protein bands in the purified CATSPER1 complex were subjected to mass spectrometry identification. Confirmed CATSPER1 interactors are listed (blue). The CATSPER channel in the testis is comprised of a macromolecular complex of all four α subunits (CATSPERS1-4), two previously identified auxiliary subunits (CATSPERβ and γ) and a novel auxiliary subunit, TMEM146 (CATSPERδ). (b and c) Two transmembrane proteins that did not express specifically in testes, SLC39A7 (band 5) and SLC39A6 (band 12), were tested for potential interaction with CATSPER1. Anti-SLC39A7 antibody recognized protein in spermatozoa, but its expression was not CATSPER1-dependent. Interaction with CATSPER1 was not found in testis (b). SLC39A6 antibody detected recombinant protein expressed in HEK293T cells ((+) CTL), but no protein was detected in sperm cells or in the CATSPER1 complex (c). (d and e) Two novel testis-specific proteins from band 12 were tested for potential interaction with CATSPER1. LOC75721 was expressed in testis but not in the CATSPER1 immune complex or sperm cells (d). Another protein identified from band12, TMEM146/CATSPERδ co-immunoprecipitates with CATSPER1 (e).