ABSTRACT
Lichen myxedematosus is an idiopathic, cutaneous mucinosis with 2 clinicopathologic subsets. There is the generalised papular and sclerodermoid form, more properly termed scleromyxedema, and the localised papular form. We report the first case, to our knowledge, of lichen myxedematosus in association with rheumatoid arthritis as well as a case in association with dermatomyositis. An up-to-date literature review on cutaneous mucinoses and connective tissue diseases, excluding the common association of primary and secondary mucinoses with systemic lupus erythematosus, was also performed.
Subject(s)
Connective Tissue Diseases , Mucinoses , Humans , Male , Middle Aged , Scleromyxedema , Skin/pathologyABSTRACT
Death receptor-dependent apoptosis is an important mechanism of growth control. It has been demonstrated that Ras association domain family protein 1A (RASSF1A) is a tumor suppressor protein involved in death receptor-dependent apoptosis. However, it is unclear how RASSF1A-mediated cell death is initiated. We have now detailed 14-3-3 dependent regulation of RASSF1A-mediated cell death. We demonstrate that basal association of RASSF1A with 14-3-3 was lost following stimulation with tumor necrosis factor alpha (TNFalpha) or TNFalpha related apoptosis inducing ligand (TRAIL). Subsequent to the loss of 14-3-3 association, RASSF1A associated with modulator of apoptosis (MOAP-1) followed by death receptor association with either TNFalpha receptor 1 (TNF-R1) or TRAIL receptor 1 (TRAIL-R1). 14-3-3 association required basal phosphorylation by the serine/threonine kinase, glycogen synthase kinase 3beta (GSK-3beta), on serine 175, 178, and 179. Mutation of these critical serines resulted in the loss of 14-3-3 association and earlier recruitment of RASSF1A to MOAP-1, TNF-R1, and TRAIL-R1. Furthermore, stable cells containing a triple serine mutant of RASSF1A [serine (S) 175 to alanine (A) [S175A], S178A, and S179A] resulted in increased basal cell death, enhanced Annexin V staining and enhanced cleavage of poly (ADP-ribose) polymerase (PARP) following TNFalpha stimulation when compared to stable cells containing wild type RASSF1A. RASSF1A-mediated cell death is, therefore, tightly controlled by 14-3-3 association.