Effects of Different Exercise Training Protocols on Gene Expression of Rac1 and PAK1 in Healthy Rat Fast- and Slow-Type Muscles

Saara Laine, Heidi Högel, Tamiko Ishizu, Jussi Toivanen, Minna Yli-Karjanmaa, Tove J Grönroos, Juha Rantala, Rami Mäkelä, Jarna C Hannukainen, Kari K Kalliokoski, Ilkka Heinonen

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2 Citations (Scopus)
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PURPOSE: Rac1 and its downstream target PAK1 are novel regulators of insulin and exercise-induced glucose uptake in skeletal muscle. However, it is not yet understood how different training intensities affect the expression of these proteins. Therefore, we studied the effects of high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) on Rac1 and PAK1 expression in fast-type (gastrocnemius, GC) and slow-type (soleus, SOL) muscles in rats after HIIT and MICT swimming exercises. METHODS: The mRNA expression was determined using qPCR and protein expression levels with reverse-phase protein microarray (RPPA). RESULTS: HIIT significantly decreased Rac1 mRNA expression in GC compared to MICT (p = 0.003) and to the control group (CON) (p = 0.001). At the protein level Rac1 was increased in GC in both training groups, but only the difference between HIIT and CON was significant (p = 0.02). HIIT caused significant decrease of PAK1 mRNA expression in GC compared to MICT (p = 0.007) and to CON (p = 0.001). At the protein level, HIIT increased PAK1 expression in GC compared to MICT and CON (by ∼17%), but the difference was not statistically significant (p = 0.3, p = 0.2, respectively). There were no significant differences in the Rac1 or PAK1 expression in SOL between the groups. CONCLUSION: Our results indicate that HIIT, but not MICT, decreases Rac1 and PAK1 mRNA expression and increases the protein expression of especially Rac1 but only in fast-type muscle. These exercise training findings may reveal new therapeutic targets to treat patients with metabolic diseases.
Original languageEnglish
JournalFrontiers in Physiology
Publication statusPublished - 19 Nov 2020
MoE publication typeA1 Journal article-refereed


  • HIIT
  • MICT
  • PAK1
  • RPPA
  • Rac1
  • exercise
  • glucose uptake
  • skeletal muscle


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