CK1 constitutes a protein kinase subfamily that is involved in many important physiological processes. However, there is limited knowledge about mechanisms that regulate their activity. Isoforms CK1delta and CK1epsilon were previously shown to autophosphorylate carboxy-terminal sites, a process which effectively inhibits their catalytic activity. Mass spectrometry of CK1alpha and splice variant CK1alphaL has identified the autophosphorylation of the last four carboxyl-end serines and threonines and also for CK1alphaS, the same four residues plus threonine-327 and serine-332 of the S insert. Autophosphorylation occurs while the recombinant proteins are expressed in Escherichia coli. Mutation of four carboxy-terminal phosphorylation sites of CK1alpha to alanine demonstrates that these residues are the principal but not unique sites of autophosphorylation. Treatment of autophosphorylated CK1alpha and CK1alphaS with lambda phosphatase causes an activation of 80-100% and 300%, respectively. Similar treatment fails to stimulate the CK1alpha mutants lacking autophosphorylation sites. Incubation of dephosphorylated enzymes with ATP to allow renewed autophosphorylation causes significant inhibition of CK1alpha and CK1alphaS. The substrate for these studies was a synthetic canonical peptide for CK1 (RRKDLHDDEEDEAMS*ITA). The stimulation of activity seen upon dephosphorylation of CK1alpha and CK1alphaS was also observed using the known CK1 protein substrates DARPP-32, beta-catenin, and CK2beta, which have different CK1 recognition sequences. Autophosphorylation effects on CK1alpha activity are not due to changes in Km(app) for ATP or for peptide substrate but rather to the catalytic efficiency per pmol of enzyme. This work demonstrates that CK1alpha and its splice variants can be regulated by their autophosphorylation status.

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Rapidly progressive glomerulonephritis is a medical emergency, with mortality around 20%. It is characterized by crescent glomerulonephritis and progressive loss of kidney function, hematuria, and proteinuria. Its classification is given by immunofluorescence detection of antibodies against glomerular basement membrane (Anti-MBG), immunocomplexes, or pauci-immune pattern. Its etiology should be based on clinical findings, immunological profile, age, sex, and histopathological characteristics. We present a case of a 27-year-old woman with symptoms consistent with rapidly progressive glomerulonephritis and biopsy findings of a full-house kidney nephropathy, with an early fatal outcome. An association of low incidence, as it is a case with a full-house pattern, and an autoimmune profile for negative systemic lupus erythematosus makes this a rare case. ANCA-associated vasculitis with full-house kidney disease was diagnosed, an unusual condition with up to 3% presentation and few reports in the literature, highlighting the importance of its reporting and contribution to the literature.