Identification of binding partners interacting with the α1-N-propeptide of type V collagen.
The predominant form of type V collagen is the [α1(V)]₂α2(V) heterotrimer. Mutations in COL5A1 or COL5A2, encoding respectively the α1(V)- and α2(V)-collagen chain, cause classic EDS (Ehlers-Danlos syndrome), a heritable connective tissue disorder, characterized by fragile hyperextensible skin and joint hypermobility. Approximately half of the classic EDS cases remain unexplained. Type V collagen controls collagen fibrillogenesis through its conserved α1(V)-N-propeptide domain. To gain an insight into the role of this domain, a yeast two-hybrid screen among proteins expressed in human dermal fibroblasts was performed utilizing the N-propeptide as a bait. We identified 12 interacting proteins, including extracellular matrix proteins and proteins involved in collagen biosynthesis. Eleven interactions were confirmed by surface plasmon resonance and/or co-immunoprecipitation: α1(I)- and α2(I)-collagen chains, α1(VI)-, α2(VI)- and α3(VI)-collagen chains, tenascin-C, fibronectin, PCPE-1 (procollagen C-proteinase enhancer-1), TIMP-1 (tissue inhibitor of metalloproteinases-1), MMP-2 (matrix metalloproteinase 2) and TGF-β1 (transforming growth factor β1). Solid-phase binding assays confirmed the involvement of the α1(V)-N-propeptide in the interaction between native type V collagen and type VI collagen, suggesting a bridging function of this protein complex in the cell-matrix environment. Enzymatic studies showed that processing of the α1(V)-N-propeptide by BMP-1 (bone morphogenetic protein 1)/procollagen C-proteinase is enhanced by PCPE-1. These interactions are likely to be involved in extracellular matrix homoeostasis and their disruption could explain the pathogenetic mechanism in unresolved classic EDS cases.
Symoens
Sofie
S
Center for Medical Genetics, Ghent University Hospital, Belgium.
Renard
Marjolijn
M
Bonod-Bidaud
Christelle
C
Syx
Delfien
D
Vaganay
Elisabeth
E
Malfait
Fransiska
F
Ricard-Blum
Sylvie
S
Kessler
Efrat
E
Van Laer
Lut
L
Coucke
Paul
P
Ruggiero
Florence
F
De Paepe
Anne
A
D024062:Collagen Type V / Q000378:metabolism*; D004535:Ehlers-Danlos Syndrome / Q000378:metabolism*; D057809:HEK293 Cells; D006706:Homeostasis; D006801:Humans; D010455:Peptides / Q000378:metabolism*; D011347:Procollagen / Q000378:metabolism*; D011485:Protein Binding
D024062:Collagen Type V; D010455:Peptides; D011347:Procollagen