页 1 从 160 结果
Calcification of the human lens has been described in senile cataracts and in young patients with congenital cataract or chronic uveitis. Lens calcification is also a major complication of cataract surgery and plays a role in the opacification of intraocular lenses. A cell-mediated process has been
Protein tyrosyl phosphorylation and dephosphorylation play essential roles in regulating cellular events such as proliferation and differentiation, and their involvement in the lens development and transparency is also suggested. The level of tyrosine phosphorylation in a given protein is regulated
The anterior lens epithelial cells undergo a variety of degenerative and proliferative changes during cataract formation. Acid phosphatase is primarily responsible for tissue regeneration and tissue repair. The lipid hydroperoxides that are obtained by lipid peroxidation of polysaturated or
Small heat shock proteins and alpha-crystallins are related proteins with several common structural and functional properties including homologous amino acid sequences and similar chaperone-like activity. Furthermore, small heat shock proteins and alpha-crystallins are phosphorylated in vivo at
Acid hydrolases (acid phophatase, N-acetyl-beta-D-glucosaminidase, alpha-D-mannosidase, alpha-L-fucosidase, and beta-D-glucuronidase) in the bovine lens epithelium were studied biochemically. p-Nitrophenyl derivatives were used as substrate. All enzymatic activity was found to be much higher in the
OBJECTIVE
To determine whether the purinergic receptor-mediated, delayed transient inhibition of lens cell-to-cell communication is due to the protein kinase C (PKC)-catalyzed phosphorylation of connexin (Cx)43.
METHODS
The functional activity of gap junctions was determined in the presence of
Activity of phosphotyrosine-protein phosphatases (PTPases) has been investigated in the different cellular regions of bovine eye lens. PTPases were tested in cellular detergent extracts using phospholabelled synthetic peptides and p-nitrophenyl phosphate. We show that a high PTPase activity is only
OBJECTIVE
To develop an in vivo model system in which exogenous proteins can be expressed in embryonic chick lens and to further understand the function of connexin-mediated gap junction intercellular communication in lens cell biology.
METHODS
RCAS(A) is a replication-competent chicken retrovirus
The present communication reports the presence of a phosphoprotein phosphatase activity in bovine lens preparations which dephosphorylates alpha Ap, the phosphorylated form of alpha A, one of the alpha-crystallin polypeptides, in a Ca2+/calmodulin dependent manner. The activity was found in soluble
OBJECTIVE
To map the cellular and subcellular distribution of DNase IIbeta activity in the mouse lens.
METHODS
DNase IIbeta-specific activity was determined by assaying lens lysates prepared from wild-type or DNase IIbeta-null mice. Regional nuclease activity was determined by microdissection of
OBJECTIVE
To study in both in situ and primary cultures the posttranslational phosphorylation of connexin46 (Cx46), one of two members of the connexin family of gap junction proteins expressed by lens fibers.
METHODS
Phosphatase digestion, gel electrophoresis, cell culture, organ culture,
A magnesium-dependent phosphatase with a molecular weight of about 55 kDa was found in the lens of chicken embryo, mouse, rabbit and bovine. It appears to be unique to the lens and, when activated by magnesium, accounts for the majority of the phosphatase activity in the lens. Phosphatases in the
The postnatal vertebrate eye lens provides an opportunity to study possible involvement of reversible protein phosphorylation in the differentiation process of epithelial cells. Epithelial cells at the lens equator, indeed, differentiate continuously into fiber cells throughout life but this