Structural and biochemical characterisation of the regulatory principles of twitchin kinase, a member of the titin-like family of muscle kinases

Williams, RM (2016) Structural and biochemical characterisation of the regulatory principles of twitchin kinase, a member of the titin-like family of muscle kinases. PhD thesis, University of Liverpool.

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Abstract

The titin-like kinases are mechanotransducers of stretch-activated signalling pathways in the muscle sarcomere, thought to undergo mechanoactivation in response to stretch in the myofibril. This work explores the mechanistic principles of twitchin kinase, a titin-like kinase from Caenorhabditis elegans. We show that twitchin kinase undergoes extensive autophosphorylation of its catalytic domain, identifying four modification sites in key mechanistic regions. We find that twitchin kinase is not activated by autophosphorylation as is common in protein kinases, but uses autophosphorylation to inhibit catalysis. We conclude that modification of the twitchin kinase substrate-binding region is likely to be a major contributor to inhibition, with phosphorylation at multiple sites having a cumulative effect to silence catalysis. We present the crystal structure of the active twitchin kinase conformation, showing that conformational changes in twitchin kinase are limited to closure of the glycine-rich loop, with the aC-helix adopting an unusually open conformation while still maintaining catalytically essential active site interactions. Our structure supports the hypothesis of mechanical activation, in which significant ... (continues)

Item Type:	Thesis (PhD)
Divisions:	Faculty of Health and Life Sciences > Faculty of Health and Life Sciences
Depositing User:	Symplectic Admin
Date Deposited:	07 Sep 2017 12:58
Last Modified:	26 Oct 2024 13:41
DOI:	10.17638/03006993
Supervisors:	Mayans, O Rigden, D ORCID: 0000-0002-7565-8937
URI:	https://livrepository.liverpool.ac.uk/id/eprint/3006993