Identification of TBC1D1 as PAS-160 in TA muscle. A, to
determine whether AS160 was the phospho-Akt-substrate detected at a molecular
weight of 160 (PAS-160) in soleus and tibialis anterior muscle, AS160 was
immunoprecipitated from insulin-stimulated soleus and tibialis anterior muscle
lysates. Lysates, supernatants, and immunoprecipitated AS160 were
immunoblotted (IB) for both AS160 and PAS-160. Gels for AS160 and
PAS-160 immunoblots were loaded identically with volume equivalents of lysates
and supernatants and a supra-proportional amount of AS160 immunoprecipitate to
compensate for inefficient elution. AS160 and PAS-160 immunodepletion and
immunoprecipitation patterns matched in soleus but not tibialis anterior
muscle. B, to determine the identity of PAS-160 in tibialis anterior
muscle, lysates were first immunodepleted of AS160; then the PAS antibody was
used to immunoprecipitate the remaining PAS-160. AS160 and PAS-160
immunoprecipitates were subjected to SDS-PAGE and stained with Coomassie Blue.
The AS160 and PAS-160 bands were excised from the gel and identified by mass
spectrometry. The identity of AS160 was confirmed, and PAS-160 was identified
as TBC1D1.