Lack of plakophilin 1 increases keratinocyte migration and reduces desmosome stability.
Ablation of the desmosomal plaque component plakophilin 1 underlies the autosomal recessive genodermatosis, skin fragility-ectodermal dysplasia syndrome (OMIM 604536). Skin from affected patients is thickened with increased scale, and there is loss of adhesion between adjacent keratinocytes, which exhibit few small, poorly formed desmosomes. To investigate further the influence of plakophilin 1 on keratinocyte adhesion and desmosome morphology, we compared plakophilin 1-deficient keratinocytes (vector controls) with those expressing recombinant plakophilin 1 introduced by retroviral transduction. We found that plakophilin 1 increases desmosomal protein content within the cell rather than enhancing transcriptional levels of desmosomal genes. Re-expression of plakophilin 1 in null cells retards cell migration but does not alter keratinocyte cell growth. Confluent sheets of plakophilin 1-deficient keratinocytes display fewer calcium-independent desmosomes than do plakophilin 1-deficient keratinocytes expressing recombinant plakophilin 1 or keratinocytes expressing endogenous plakophilin 1. In addition electron microscopy studies show that re-expression of plakophilin 1 affects desmosome size and number. Collectively, these results demonstrate that restoration of plakophilin 1 function in our culture system influences the transition of desmosomes from a calcium-dependent to a calcium-independent state and this correlates with altered keratinocyte migration in response to wounding. Thus, plakophilin 1 has a key role in increasing desmosomal protein content, in desmosome assembly, and in regulating cell migration.
South
Andrew P
AP
Department of Cell and Molecular Pathology, St John's Institute of Dermatology, Guy's, King's and St Thomas' School of Medicine, London, UK. andrew.south@kcl.ac.uk
Wan
Hong
H
Stone
Michael G
MG
Dopping-Hepenstal
Patricia J C
PJ
Purkis
Patricia E
PE
Marshall
John F
JF
Leigh
Irene M
IM
Eady
Robin A J
RA
Hart
Ian R
IR
McGrath
John A
JA
D016475:3T3 Cells; D000818:Animals; D015820:Cadherins / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D002448:Cell Adhesion / Q000502:physiology; D015815:Cell Adhesion Molecules / Q000378:metabolism; D002455:Cell Division; D002465:Cell Movement / Q000502:physiology*; D002478:Cells, Cultured; D003598:Cytoskeletal Proteins / Q000378:metabolism; D051184:Desmoglein 3; D051180:Desmoplakins; D003896:Desmosomes / Q000378:metabolism*; D005260:Female; D006801:Humans; D015603:Keratinocytes / Q000166:cytology / Q000378:metabolism*; D007633:Keratins / Q000378:metabolism; D008297:Male; D051379:Mice; D008854:Microscopy, Electron; D051191:Plakophilins; D011506:Proteins / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D012867:Skin / Q000166:cytology / Q000378:metabolism*; D012871:Skin Diseases / Q000378:metabolism; D015534:Trans-Activators / Q000378:metabolism; D051176:beta Catenin
C495270:CTNNB1 protein, human; C495267:CTNNB1 protein, mouse; D015820:Cadherins; D015815:Cell Adhesion Molecules; D003598:Cytoskeletal Proteins; C071894:DSG3 protein, human; D051184:Desmoglein 3; D051180:Desmoplakins; C495335:PKP1 protein, human; C495336:Pkp1 protein, mouse; D051191:Plakophilins; D011506:Proteins; D012333:RNA, Messenger; D015534:Trans-Activators; D051176:beta Catenin; D007633:Keratins; D002118:Calcium