OBJECTIVESTo investigate the androgen receptor (AR) isoforms expression in human benign and malignant prostatic tissues and LNCaP cells.

METHODSUsing high resolution isoelectric focusing (IEF), the different expression of AR isoforms were demosntrated in human benign and malignant prostatic tissues and LNCaP cells.

RESULTSData were obtained from 41 AR-positive BPH, three prostatic cancer specimens, and LNCaP cells. From these materials, three types of AR isoforms were detected with pI values at 6.5, 6.0 and 5.3. In the case of BPH tissues, 15 (36.5%) specimens expressed all the three types of isoforms at pI 6.5, 6.0 and 5.3, and 10 (24.4%) samples contained isoforms at pI 6.5 and 5.3, five (12.2%) samples indicated isoforms at pI 6.5 and 6.0, four (9.8%) showed the isoforms at pI 6.0 and 5.3. Of all the 41 specimens, two (4.9%) and two (4.9%) as well as three (7.3%) denoted the isoforme at pI 6.5, 6.0 and 5.3 respectively. As for three prostatic cancer specimens, one sample showed all the three types of AR isoforms at pI 6.5, 6.0, 5.3, but another specimen expressed at pI 6.5 and 6.0, and only one failed to indicate any types of isoforms. LNCaP cells expressed all three types of AR isoforms at pI 6.5, 6.0 and 5.3. Binding of 3H-dihydrotestosterone to these three types of isoforms was inhibited by the addition of 100-fold excess of DHT and testosterone. No effect of progesterone, oestradiol and diethylstilboestrol on tritiated hormone binding was observed.

CONCLUSIONSThe expression of AR isoforms is different among various patients and different between BPH and LNCaP cells, though no clear explanation could be induced for this. These results suggest the possibility of explaining effective hormonal therapy to prostatic disease in the future.

Humans ; Male ; Prostate ; metabolism ; Protein Isoforms ; metabolism ; Receptors, Androgen ; metabolism ; Tumor Cells, Cultured

The distribution of caveolin isoforms was previouslyevaluated in the retinas of different species, but has notyet been described in the primate retina. In this study, thedistribution of caveolins was assessed via immunochemistryusing isoform-specific antibodies in the retina of the black-and-white ruffed lemur. Here, we report the presence of avariety of caveolin isoforms in many layers of the lemurretina. As normal human retinas were not available forresearch and the retinas of primates are fairly similar tothose of humans, the lemur retina can be utilized as amodel for caveolin distribution in normal humans.
Animals ; Caveolins/*metabolism ; Immunohistochemistry ; Lemur/*metabolism ; Male ; Protein Isoforms ; Retina/*metabolism

Titin, the largest known protein in the body expressed in three isoforms (N2A, N2BA and N2B), is essential for muscle structure, force generation, conduction and regulation. Since the 1950s, muscle contraction mechanisms have been explained by the sliding filament theory involving thin and thick muscle filaments, while the contribution of cytoskeleton in force generation and conduction was ignored. With the discovery of insoluble protein residues and large molecular weight proteins in muscle fibers, the third myofilament, titin, has been identified and attracted a lot of interests. The development of single molecule mechanics and gene sequencing technology further contributed to the extensive studies on the arrangement, structure, elastic properties and components of titin in sarcomere. Therefore, this paper reviews the structure, isforms classification, elastic function and regulatory factors of titin, to provide better understanding of titin.
Connectin/genetics* ; Muscle Proteins/metabolism* ; Protein Isoforms/genetics* ; Sarcomeres/metabolism* ; Muscle Fibers, Skeletal/metabolism*

Lipoxygenases (linoleate: oxygen oxidoreductase, EC 1.13.11.12; LOXs) are encoded by a multi-gene family in plants. The LOXs are monomeric non-heme, non-sulfur iron dioxygenases, which catalyze the incorporation of molecular oxygen into polyunsaturated fatty acids containing a cis, cis-1,4-pentadiene moiety. The LOX isoforms are distinguished by differences in optimum pH of the reaction, pI, substrate and product specificity, spatial and temporal expression, and subcellular localization. The function of various LOXs in plants has been suggested. Some of the physiological processes in which lipoxygenases have been implicated include wounding, pathogen attack, seed germination, fruit ripening, plant senescence, and synthesis of Abscisic acid (ABA) and Jasmonic acid (JA). During normal vegetative and reproductive growth, lipoxygenases have also been suggested to act as vegetative storage proteins, participate in transference of lipoid, and response to nutrient stress and source/sink relationships. Significant progress in understanding LOX families will be beneficial to the application of the LOX in crop breeding, research on new-type phytoalexin and food industry.
Gene Expression Regulation, Plant ; Lipoxygenase ; genetics ; metabolism ; Multigene Family ; Plants ; enzymology ; Protein Isoforms ; genetics ; metabolism

Vascular endothelial growth factor-A (VEGF-A) is a critical angiogenic factor which is mainly secreted from podocytes and epithelial cells in kidney and plays an important role in renal pathophysiology. In recent years, functions of different isoforms of VEGF-A and the new secretion approach via extracellular vesicles (EVs) have been identified. Thus, further understanding are needed for the role of VEGF-A and its isoforms in renal injury and repair. In this review, we summarized the expression, secretion and regulation of VEGF-A, its biological function, and the role of different isoforms of VEGF-A in the development of different renal diseases. Meanwhile, the research progress of VEGF-A as diagnostic marker and therapeutic target for renal diseases were discussed.
Humans ; Kidney/metabolism* ; Kidney Diseases ; Protein Isoforms/metabolism* ; Vascular Endothelial Growth Factor A/physiology*

Arabidopsis ; metabolism ; Catalytic Domain ; Dimerization ; Glutathione ; metabolism ; Magnetic Resonance Spectroscopy ; Populus ; metabolism ; Protein Disulfide Reductase (Glutathione) ; chemistry ; metabolism ; Protein Isoforms ; chemistry ; metabolism ; Protein Structure, Tertiary

OBJECTIVETo investigate the expression of androgen receptor (AR) isoforms in normal human prostate.

METHODSFourteen normal prostatic specimens from donors, aged 25 on average (21-28 yr), were analyzed by high resolution isoelectric focusing (IEF). The expression of AR isoforms was demonstrated in all 14 normal human prostatic tissues.

RESULTSFour types of AR isoforms were detected with isoelectric point value at 6.5, 6.0, 5.8 and 5.3 in 14 prostatic specimens. Binding of 3H-dihydrotestosterone (DHT) to these four AR isoforms was inhibited by the addition of 100-fold excess of DHT and testosterone. No effect of progesterone, estradiol and diethylstilbestrol on tritiated hormone binding was observed.

CONCLUSIONSThere are four AR isoforms in normal human prostate. The expression of AR isoforms is different from one another.

Adult ; Humans ; Isoelectric Focusing ; Isoelectric Point ; Male ; Prostate ; metabolism ; Protein Isoforms ; biosynthesis ; Receptors, Androgen ; biosynthesis

Peroxiredoxins (Prxs) are antioxidant enzymes that protect cells from oxidative stress by reducing intracellular accumulation of reactive oxygen species (ROS). In mammalian cells, the six Prx isoforms are ubiquitously expressed in diverse intracellular locations. They are involved in the regulation of various physiological processes including cell growth, differentiation, apoptosis, immune response and metabolism as well as intracellular ROS homeostasis. Although there are increasing evidences that Prxs are involved in carcinogenesis of many cancers, their role in cancer is controversial. The ROS levels in cancer cells are increased compared to normal cells, thus promoting cancer development. Nevertheless, for various cancer types, an overexpression of Prxs has been found to be associated with poor patient prognosis, and an increasing number of studies have reported that tumorigenesis is either facilitated or inhibited by regulation of cancer-associated signaling pathways. This review summarizes Prx isoforms and their basic functions, the relationship between the expression level and the physiological role of Prxs in cancer cells, and their roles in regulating cancer-associated signaling pathways.
Apoptosis ; Carcinogenesis ; Homeostasis ; Humans ; Metabolism ; Oxidative Stress ; Peroxiredoxins ; Physiological Processes ; Prognosis ; Protein Isoforms ; Reactive Oxygen Species

The Wilms' tumor gene (WT1) is a transcription factor involved in tumorigenesis, especially in leukemogenesis. However, the role of WT1 expression in nonmalignant hematopoietic cells remains unclear. Furthermore, due to alternative splicing at two sites: 17 amino acid residues of exon 5 (+17AA) and 3 amino acid residues (+KTS) between exons 9 and 10, WT1 gene has four main isoforms (17AA+/KTS+, 17AA+/KTS-, 17AA-/KTS+, 17AA-/KTS-, abbreviation: +/+, +/-, -/+, -/-). The isoforms probably existed in hematopoietic cells, which make the research more complex. The aim of study was to elucidate the expression and its isoforms of WT1 gene in different cell subsets of healthy bone marrow donors. The fluorescence RT-PCR detection system was established to measure the expressions of full-length WT1, WT1 (+17AA) and WT1 (+KTS) in CD34(+)CD38(-) (stem cell), CD34(+)CD38(+) (progenitor cell), CD15(+)CD11b(+) (granulocyte), CD33(+)CD14(+) (monocyte), CD20(+)CD5(-) (B-lymphocyte) and CD20(-)CD5(+) (T-lymphocyte) subsets from 18 normal human bone marrow samples. The results showed that WT1 expressed in CD34(+)CD38(-), CD34(+)CD38(+), CD15(+)CD11b(+) and CD33(+)CD14(+), but not in CD20(+)CD5(-) and CD20(-)CD5(+) subsets. The highest expression was in CD34(+)CD38(-), but decreased gradually in CD15(+)CD11b(+) and CD33(+)CD14(+) subsets. WT1 (+17AA), WT1 (+KTS) and WT1 (+/+) isoforms were predominant in CD34(+)CD38(-) and CD34(+)CD38(+) primitive subsets, while in CD15(+)CD11b(+) and CD33(+)CD14(+) the dominant isoforms were WT1 (-17AA), WT1 (-KTS) and WT1 (-/-). It is concluded that the expression of WT1 in normal bone marrow decreases gradually with cell differentiation. Hematopoietic cells may adjust the ratios of WT1 isoforms to inhibit or promote cell differentiation.
Antigens, CD34 ; analysis ; Bone Marrow Cells ; metabolism ; Cell Differentiation ; Gene Expression Regulation ; Humans ; Protein Isoforms ; metabolism ; WT1 Proteins ; metabolism

Humans ; Inhibitor of Apoptosis Proteins ; Microtubule-Associated Proteins ; genetics ; metabolism ; Protein Isoforms ; genetics ; metabolism ; Stomach Neoplasms ; genetics ; metabolism ; Tumor Cells, Cultured