When chaperone and proteasome systems are impaired, ubiquitinated proteins are transported along microtubules to aggresomes. Histone deacetylase 6 (HDAC6) is a key factor for aggresome formation, since it has ubiquitinated protein and dynein motor binding domains. In addition, HDAC6 deacetylates α-tubulin and regulates microtubule stability. In this study, we examined changes in the acetylation level of α-tubulin by HDAC6 in the development of heart failure (HF) after myocardial infarction (MI). MI was induced by coronary artery ligation (CAL). Hemodynamic parameters at the 8th (8W), but not 2nd (2W), week after CAL showed signs of HF. Myocardial HDAC6 and acetylated α-tubulin contents were increased in 2W-CAL rats, whereas those in 8W-CAL rats were similar to the corresponding Sham rats. These findings indicate that changes in HDAC6 content are not consistent with the acetylation level of α-tubulin after CAL. We focused on Ran-binding protein M (RanBPM), which interacts with HDAC6 to suppress its activity. Changes in content of RanBPM after CAL were similar to those of HDAC6. These results suggest that RanBPM enhances microtubule stability through a suppression of HDAC6 activity and promotes aggresome formation.