Evidence for filaggrin as a component of the cell envelope of the newborn rat.
A substrate of transglutaminase, specific to the epidermis, was identified, by fluorescent and radioactive labelling with the lysine analogues dansylcadaverine and [14C]putrescine respectively, in newborn-rat epidermal homogenates and whole-skin organ cultures. The labelled analogues were preferentially incorporated into the stratum-corneum protein filaggrin in a Ca2+-dependent manner in both 'in vitro' systems. When filaggrin was labelled in vivo with [3H]histidine and then incubated with rat epidermal preparations, the label was rendered SDS/thiol-insoluble. Incorporation of [3H]filaggrin into the insoluble envelope fraction was Ca2+-dependent and inhibited by EDTA and exogenous amines. Antisera to newborn-rat filaggrin cross-reacted with purified newborn-rat cell envelopes, and this reaction was blocked by adsorbing the antiserum with purified filaggrin. Quantification of the 'envelope-bound' filaggrin showed it to be a significant component, accounting for approx. 10% of the cell-envelope protein.
Department of Biochemistry, University College, Cardiff, Wales, U.K.
S
S
Richards
I R
IR
Scott
C R
CR
Harding
J E
JE
Liddell
G M
GM
Powell
C G
CG
Curtis
D000818:Animals; D000831:Animals, Newborn / Q000378:metabolism*; D002103:Cadaverine / Q000031:analogs & derivatives / Q000378:metabolism; D002118:Calcium / Q000494:pharmacology; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D004817:Epidermis / Q000187:drug effects / Q000378:metabolism*; D000091344:Filaggrin Proteins; D005456:Fluorescent Dyes / Q000378:metabolism; D006639:Histidine / Q000378:metabolism; D007381:Intermediate Filament Proteins / Q000276:immunology / Q000378:metabolism*; D008856:Microscopy, Fluorescence; D009924:Organ Culture Techniques; D011700:Putrescine / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains
D000091344:Filaggrin Proteins; D005456:Fluorescent Dyes; D007381:Intermediate Filament Proteins; D006639:Histidine; C008542:monodansylcadaverine; D002103:Cadaverine; D002118:Calcium; D011700:Putrescine