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

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

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

Metallothioneins (MTs) are a group of intracellular proteins of low molecular weight and rich cysteine, encoded by a family of genes containing at least 10 functional isoforms in human. MTs widely exist in the male reproductive system and are involved in many pathophysiological processes such as metal ion homeostasis and detoxification, protection against oxidative damage, cell proliferation and apoptosis, chemoresistance and radiotherapy resistance. This review describes the location and effects of MTs in the male reproductive system.
Gene Expression Profiling ; Genitalia, Male ; metabolism ; physiopathology ; Humans ; Male ; Metallothionein ; genetics ; metabolism ; physiology ; Protein Isoforms ; genetics ; metabolism ; physiology

Over-expression of the human epidermal growth factor receptor-2 (HER2/neu) has been observed in many cancers, and is associated with a poor prognosis. Recent adjuvant treatment with anti-HER2 monoclonal antibodies in breast cancer has increased the demand for an evaluation of the HER2/neu status in breast cancer. The aim of this study was to investigate the HER2/neu status in breast cancer by a real-time quantitative polymerase chain reaction (PCR) method using LightCycler (Roche Diagnostics, Mannheim, Germany). DNA samples from the fresh tumor tissues of 27 patients with breast cancer were analyzed in parallel using immunohistochemistry (IHC) and the other prognostic parameters including estrogen receptor, progesterone receptor, cytokeratin, and DNA ploidy. Ten (37%) out of 27 cases tested were positive for HER2/neu, while 16 (73%) out of 22 tested positive through an IHC study. The correlation between the DNA aneuploidy and the positive results for HER2/neu were only observed using the real-time PCR method (p < 0.05). There was no significant correlation between the HER2/neu status and the S-phase fractions of the DNA ploidy or other parameters. This study demonstrated that there is marked discordance in the results for the HER2/neu status according to the various methods used. Real-time quantitative PCR for HER2/neu appears to be clinically useful due to its simplicity and ability to produce rapid results.
Breast Neoplasms/*metabolism ; Female ; Human ; Protein Isoforms/metabolism ; Receptor, Epidermal Growth Factor/*metabolism ; *Reverse Transcriptase Polymerase Chain Reaction