The C-terminus of PARK2 is required for its self-interaction, solubility and role in the spindle assembly checkpoint.

PARK2, an ubiquitin ligase closely correlated with Parkinson's disease and cancer, has been shown to accumulate at centrosomes to ubiquitinate misfolded proteins accumulated during interphase. In the present study, we demonstrated that PARK2 can also localize to centrosomes in mitosis and that the protein does not fluctuate through the S- to M-phase. A C-terminal truncation of PARK2 resulted in a spindle assembly checkpoint defect, characterized by HeLa cells able to bypass mitotic arrest induced by nocodazole and form multinucleated cells when overexpressing the C-terminal truncated PARK2 protein. The spindle assembly checkpoint defect may be due to a change in a biochemical or structural property of PARK2 caused by the C-terminal truncation, resulting in a loss of self-interaction between PARK2 proteins.

Smaller bladder capacity and stronger bladder contractility in patients with ketamine cystitis are associated with elevated TRPV1 and TRPV4.

Stronger contractility and smaller bladder capacity are common symptoms in ketamine cystitis (KC). This study investigates the association between expression levels of transient receptor potential cation channel subfamily V (TRPV) proteins and the clinical characteristics of KC. Bladder tissues were obtained from 24 patients with KC and four asymptomatic control subjects. Video urodynamic parameters were obtained before surgical procedures. The TRPV proteins were investigated by immunoblotting, immunofluorescence staining, and immunohistochemistry. The Pearson test was used to associate the expression levels of TRPV proteins with clinical characteristics of KC. The expression level of TRPV1 and TRPV4 was significantly higher in the severe KC bladders than in mild KC or control bladders. The TRPV1 proteins were localized in all urothelial cell layers, and TRPV4 was located in the basal cells and lamina propria. The expression of TRPV1 was negatively associated with maximal bladder capacity (r = - 0.66, P = 0.01). The expression of TRPV4 was positively associated with the velocity of detrusor pressure rise to the maximum flow rate (r = 0.53, P = 0.01). These observations suggest smaller bladder capacity and stronger contractility in KC are associated with an elevated expression of TRPV1 and TRPV4, respectively.

The putative involvement of actin-binding proteins and cytoskeleton proteins in pathological mechanisms of ketamine cystitis-Revealed by a prospective pilot study using proteomic approaches.

PURPOSE: Ketamine-induced cystitis (KC) among chronic ketamine young abusers has increased dramatically and it has brought attention for Urologists. The underlying pathophysiological mechanism(s) of KC is still unclear. Therefore, the purpose of this study is to elucidate the possible pathophysiological mechanism(s) of KC through proteomic techniques. EXPERIMENTAL DESIGN: Bladder tissues are obtained from seven patients with KC, seven patients with interstitial cystitis/bladder pain syndrome, and five control subjects who underwent video-urodynamic study followed by augmentation enterocystoplasty to increase bladder capacity. 2DE/MS/MS-based approach, functional classifications, and network analyses are used for proteomic and bioinformatics analyses and protein validation is carried out by Western blot analysis. RESULTS: Among the proteins identified, bioinformatics analyses revealed that several actin binding related proteins such as cofilin-1, myosin light polypeptide 9, filamin A, gelsolin, lamin A are involved in the apoptosis. Besides, the contractile proteins and cytoskeleton proteins such as myosin light polypeptide 9, filamin A, and calponin are found downregulated in KC bladders. CONCLUSIONS AND CLINICAL RELEVANCE: Increased apoptosis in KC might be mediated by actin-binding proteins and a Ca2+ -activated protease. Rapid detrusor contraction in KC might be induced by contractile proteins and cytoskeleton proteins.

Depletion of albumin and immunoglobulin G from human serum using epitope-imprinted polymers as artificial antibodies.

Serum is a readily available source for noninvasive studies in clinical research, but it contains abundant proteins such as albumin and immunoglobulin G that can hinder the presence of low-abundant proteins as well as decrease sample loading capacity of analytical methods. Therefore, depletion of these two proteins is required to observe low-abundance serum proteins. Molecularly imprinted polymers are template-induced artificial antibodies with the ability to recognize and selectively bind the target molecule. In this study, artificial albumin and immunoglobulin G antibodies were developed by using two epitopes of human serum albumin and immunoglobulin G as templates. Acrylic acid, acrylamide, and N-acryl tyramine were the corresponding monomers; N,N'-ethylene bisacrylamide served as a cross-linker, and cellulosic fibers were used as a supporting matrix. The adsorption capacity of these artificial antibodies was 15.2 mg, 10 mg, and 15 µL per gram for human serum albumin, immunoglobulin G, and human serum, respectively. The dissociation constant (Kd ) of these artificial antibodies toward the human serum albumin and immunoglobulin G was 1 µM and 0.6 µM, respectively. The biomimetic properties of these artificial antibodies, coupled with their economical and rapid production, high specificity and their reusability, make them attractive for protein separation and analysis.

Proteomic-based identification of multiple pathways underlying n-butylidenephthalide-induced apoptosis in LNCaP human prostate cancer cells.

Although numerous studies have shown the cancer-preventive properties of butylidenephthalide (BP), there is little report of BP affecting human prostate cancer cells. In the present study, proteomic-based approaches were used to elucidate the anticancer mechanism of BP in LNCaP human prostate cancer cells. BP treatment decreased the viability of LNCaP human prostate cancer cells in a concentration- and time-dependent manner, which was correlated with G0/G1 phase cell cycle arrest. Increased cell cycle arrest was associated with a decrease in the level of CCND1, CDK2, and PCNA proteins and an increase in the level of CDKN2A, CDKN1A, and SFN proteins. Proteomic studies revealed that among 48 differentially expressed proteins, 25 proteins were down-regulated and 23 proteins were up-regulated and these proteins fall into one large protein protein interaction network. Among these proteins, FAS, AIFM1, BIK, CYCS, SFN, PPP2R1A, CALR, HSPA5, DDIT3, and ERN1 are apoptosis and endoplasmic reticulum (ER) stress associated proteins. Proteomic data suggested that multiple signaling pathways including FAS-dependent pathway, mitochondrial pathway, and ER stress pathway are involved in the apoptosis induced by BP.