Signaling of the ITK (Interleukin 2-inducible T Cell Kinase)-SYK (Spleen Tyrosine Kinase) Fusion Kinase Is Dependent on Adapter SLP-76 and on the Adapter Function of the Kinases SYK and ZAP70

The inducible T cell kinase-spleen tyrosine kinase (ITK-SYK) oncogene consists of the Tec homology-pleckstrin homology domain of ITK and the kinase domain of SYK, and it is believed to be the cause of peripheral T cell lymphoma. We and others have recently demonstrated that this fusion protein is constitutively tyrosine-phosphorylated and is transforming both in vitro and in vivo. To gain a deeper insight into the molecular mechanism(s) underlying its activation and signaling, we mutated a total of eight tyrosines located in the SYK portion of the chimera into either phenylalanine or to the negatively charged glutamic acid. Although mutations in the interdomain-B region affected ITK-SYK kinase activity, they only modestly altered downstream signaling events. In contrast, mutations that were introduced in the kinase domain triggered severe impairment of downstream signaling. Moreover, we show here that SLP-76 is critical for ITK-SYK activation and is particularly required for the ITK-SYK-dependent phosphorylation of SYK activation loop tyrosines. In Jurkat cell lines, we demonstrate that expression of ITK-SYK fusion requires an intact SLP-76 function and significantly induces IL-2 secretion and CD69 expression. Furthermore, the SLP-76-mediated induction of IL-2 and CD69 could be further enhanced by SYK or ZAP-70, but it was independent of their kinase activity. Notably, ITK-SYK expression in SYF cells phosphorylates SLP-76 in the absence of SRC family kinases. Altogether, our data suggest that ITK-SYK exists in the active conformation state and is therefore capable of signaling without SRC family kinases or stimulation of the T cell receptor.     

Immunohistochemical analysis of connective tissue in patients with pelvic organ prolapse

The uterosacral ligaments are an important part of the pelvic support system. The objective of this study was to compare the expression of collagen type I and collagen type III in the uterosacral ligament biopsies from women with and without pelvic organ prolapse (POP). The uterosacral ligament biopsies were obtained from women with POP (n = 29) and non-POP subjects (n = 35). Immunohistochemistry for collagen type I and collagen type III was performed on formalin-fixed and paraffin-embedded sections. The two groups were matched for age, body mass index, parity and postmenopausal status. The expression of collagen type I (p < 0.001) and collagen type III (p < 0.0001) differed between women with POP and non-POP subjects. There was decreased expression of collagen type I and increased expression of collagen type III in uterosacral ligaments of women with POP compared with non-POP subjects. This difference indicates a possible relationship between POP and the immunohistochemical expression of collagen type I and collagen type III in uterosacral ligaments.     

Live Cell Imaging of Peptide Uptake Using a Microfluidic Platform

International Journal of Peptide Research and Therapeutics - Cell penetrating peptides (CPPs) are unique molecules with the ability to pass through biological membranes as they carry their cargoes...     

“Constructing” the Cell Cycle in 3D

The cycle of duplication and division, known as the cell cycle, is the essential mechanism by which all living organisms reproduce. This activity allows students to develop an understanding of the main events that occur during the typical eukaryotic cell cycle mostly in the process of mitotic phase that divides the duplicated genetic material creating two genetically identical daughter cells.     

Peripheral TREM2 mRNA levels in early and late-onset Alzheimer disease’s patients

Molecular Biology Reports - ‘Triggering receptor expressed on myeloid cells 2’ (TREM2) gene is involved in Alzheimer’s disease (AD) and TREM2 mRNA expression is known to be...     

Erratum to: Pollen Analysis,Chemical Composition and Antibacterial Activity of Anatolian Chestnut Propolis Collected from Yıgılca Region

Biology Bulletin - An Erratum to this paper has been published: https://doi.org/10.1134/S1062359022330019     

Improved activity and pH stability of E. coli ATCC 11105 penicillin acylase by error-prone PCR

Penicillin G acylase is the key enzyme used in the industrial production of β-lactam antibiotics. This enzyme hydrolyzes penicillin G and related β-lactam antibiotics releasing 6-aminopenicillanic acid, which is an intermediate in the production of semisynthetic penicillins. To improve the enzymatic activity of Escherichia coli penicillin acylase, sequential rounds of error-prone polymerase chain reaction were applied to the E. coli pac gene. After the second round of evolution, the best mutant M2234 with enhanced activity was selected and analyzed. DNA sequence analyses of M2234 revealed that one amino acid residue (K297I), located far from the center of the catalytic pocket, was changed. This mutant (M2234) has a specific activity 4.0 times higher than the parent enzyme and also displayed higher stability at pH 10.