Lamins of ocular lens epithelial cells

Unravelling the nuclear matrix proteome

The nuclear matrix (NM) model posits the presence of a protein/RNA scaffold that spans the mammalian nucleus. The NM proteins are involved in basic nuclear function and are a promising source of protein biomarkers for cancer. Importantly, the NM proteome is operationally defined as the proteins from cells and tissue that are extracted following a specific biochemical protocol; in brief, the soluble proteins and lipids, cytoskeleton, and chromatin elements are removed in a sequential fashion, leaving behind the proteins that compose the NM. So far, the NM has not been sufficiently verified as a biological entity and only preliminary at the molecular level. Here, we argue for a combined effort of proteomics, immunodetection and microscopy to unravel the composition and structure of the NM.

Effect of thermal stress on early and late passaged mouse lens epithelial cells

Cataract is an age related disease of protein aggregation. It has been suggested that aging affects the cells ability to protect protein integrity. The protein integrity, which is essential for cellular homeostasis, is maintained by a complex system of refolding or degradation of damaged proteins. The heat shock proteins (hsps) are the major contributors in the maintenance of protein integrity. The heat shock transcription factor (HSF-1) is the master regulator of all hsp synthesis in response to stress. This investigation examined the role of HSF-1 in the regulation of hsp synthesis in early and late passaged alphaTN-4 cells. Data collected in this study revealed that the nucleotide sequence of HSF-1 mRNA obtained from early and late passaged alphaTN-4 cells were identical. When early and late passaged cell were exposed to thermal stress, their hsp expression were also similar. HSP-40 expression was detected after 2 h of heat stress, whereas HSP-70 and low molecular weight heat shock protein alphabeta crystallin showed significantly increased synthesis 18 h post heat stress. The late passaged alphaTN-4 cells ability to upregulate hsps in response to heat stress could be due to its high replicative activities. The data presented here suggests a relationship between the presence of functional HSF-1 and sustained proliferative activities of the late passaged alphaTN-4 cell.