SUMOylation does not affect cardiac troponin I stability but alters indirectly the development of force in response to Ca2+

Bracy Fertig, Jiayue Ling, Edgar E. Nollet, Sara Dobi, Tara Busiau, Kiyotake Ishikawa, Kelly Yamada, Ahyoung Lee, Changwon Kho, Lauren Wills, Amy J. Tibbo, Mark Scott, Kirsten Grant, Kenneth S. Campbell, Emma J. Birks, Niall MacQuaide, Roger Hajjar, Godfrey L. Smith, Jolanda van der Velden, George S. Baillie*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

Post-translational modification of the myofilament protein troponin I by phosphorylation is known to trigger functional changes that support enhanced contraction and relaxation of the heart. We report for the first time that human troponin I can also be modified by SUMOylation at lysine 177. Functionally, TnI SUMOylation is not a factor in the development of passive and maximal force generation in response to calcium, however this modification seems to act indirectly by preventing SUMOylation of other myofilament proteins to alter calcium sensitivity and cooperativity of myofilaments. Utilising a novel, custom SUMO site-specific antibody that recognises only the SUMOylated form of troponin I, we verify that this modification occurs in human heart and that it is upregulated during disease.
Original languageEnglish
JournalFEBS Journal
Early online date2022
DOIs
Publication statusE-pub ahead of print - 2022

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