XP repair proteins
The XPA protein acts during NER as a scaffold for assembly of other DNA repair proteins at sites of DNA damage to ensure appropriate excision of the damage.The XPB (ERCC3) protein is employed in unwinding the DNA double helix after DNA damage is initially recognized. Mutations in the XPB(ERCC3) gene can lead to XP or XP combined with Cockayne syndrome.The XPC protein forms a complex with RAD23B protein to form the initial damage recognition factor in global genomic nucleotide excision repair (GG-NER). This complex recognizes a wide variety of damages that thermodynamically destabilize DNA duplexes.The XPD (ERCC2) protein, in combination with the XPB helicase-containing transcription/repair complex TFIIH, is employed in unwinding the DNA duplex after damage is initially recognized. Mutations in the XPD(ERCC2) gene cause a variety of syndromes; XP, trichothiodystrophy (TTD), or a combination of XP and Cockayne syndrome (XPCS). Both trichothiodystrophy and Cockayne syndrome display features of premature aging, suggesting an association between deficient DNA repair and premature aging (see DNA damage theory of aging). XPE is a heterodimeric protein composed of two subunits. The larger subunit DDB1 primarily functions as a core component of CUL4A- and CUL4B-based E3 ubiquitin ligase complexes. Substrates that are ubiquitinnated by these complexes include proteins employed in DNA repair.The XPF (ERCC4) protein together with the ERCC1 protein forms a complex usually designated ERCC1-XPF. This complex separates the DNA helix for a short distance on either side of the site of damage.
Roflumilast, sold under the trade name Daxas among others, is a drug that acts as a selective, long-acting inhibitor of the enzyme phosphodiesterase-4 (PDE-4). It has anti-inflammatory effects and is used as an orally administered drug for the treatment of inflammatory conditions of the lungs such as chronic obstructive pulmonary disease (COPD).In June 2010, it was approved in the European Union for severe COPD associated with chronic bronchitis. In February 2011, it gained FDA approval in the United States for reducing COPD exacerbations. Medical uses
Roflumilast is indicated for the treatment of severe chronic obstructive pulmonary disease (COPD) and for the treatment of plaque psoriasis.It is used in the prevention of exacerbations (lung attacks) in severe chronic obstructive pulmonary disease (COPD).A topical formulation of Rolflumilast was recently approved by the U.S. Food and Drug Administration for plaque psoriasis. Adverse effects
Common (1–10% incidence) adverse effects include:
Diarrhea
Weight loss
Nausea
Headache
Insomnia
Decreased appetite
Abdominal pain
Rhinitis
Sinusitis
Urinary tract infection
Depression

References
External links
"Roflumilast". Drug Information Portal. U.S. National Library of Medicine.