Regulation of fibrillin-1 processing and microfibril assembly by pro-protein convertases

  • Alan Godwin

Student thesis: Unknown


The University of ManchesterAbstract of thesis submitted by Alan Robert Francis Godwin for the degree of Master of Philosophy entitled 'Regulation of fibrillin-1 processing and microfibril assembly by pro-protein convertases'. September 2012.Fibrillin-1 is the major component of a class of microfibrils which form the scaffold for the deposition of elastin in elastic tissues such as the aorta, elastic arteries, skin, lung and auricular cartilage. Mutations in fibrillin-1 lead to a number of inheritable connective tissue disorders collectively termed fibrillinopathies, which include diseases such as Marfan syndrome and Weill Marchesani syndrome.Fibrillin-1 contains recognition sequences for the pro-protein convertase family of serine proteases in its N- and C-terminal regions. Cleavage at the C-terminus has been shown to be a critical step in the assembly of fibrillin-1. Mutations have been identified which prevent C-terminal processing of fibrillin-1, which in turn cause Marfan syndrome. N-terminal processing is also likely to be an important step in microfibril deposition.For the first time, N-terminal processing of fibrillin-1 has been monitored using a cell culture model expressing full-length N-terminally V5-tagged recombinant fibrillin-1. N-terminal processing was shown to be sensitive to the addition of exogenous heparin. Addition of the pro-protein convertase inhibitor hexa-D-arginine suggests that N-terminal processing may not be essential for the "head-to-tail" assembly of fibrillin-1 into microfibrils.Using RNA interference to target enzymes of the pro-protein convertase family, it was determined that furin was the major enzyme involved in the C-terminal processing of fibrillin-1. This processing of the C-terminus, however, was not sensitive to the addition of exogenous heparin, or to the depletion of heparan sulphate using RNA interference of exostosin-1 (an early heparan sulphate polymerase).These results give new insights into the role and regulation of fibrillin-1 processing in the formation of fibrillin-1 microfibrils, and highlight the importance of heparan sulphate interactions in N-terminal cleavage by the pro-protein convertases
Date of Award1 Aug 2013
Original languageEnglish
Awarding Institution
  • The University of Manchester
SupervisorClair Baldock (Supervisor), Michael Sherratt (Supervisor), Anthony Day (Supervisor) & Alan Roseman (Supervisor)

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