The Syk tyrosine kinase suppresses malignant growth of human breast cancer cells

Syk is a protein tyrosine kinase that is widely expressed in haematopoietic cells. It is involved in coupling activated immunoreceptors to downstream signalling events that mediate diverse cellular responses including proliferation, differentiation and phagocytosis. Syk expression has been reported in cell lines of epithelial origin, but its function in these cells remains unknown. Here we show that Syk is commonly expressed in normal human breast tissue, benign breast lesions and low-tumorigenic breast cancer cell lines. Syk messenger RNA and protein, however, are low or undetectable in invasive breast carcinoma tissue and cell lines. Transfection of wild-type Syk into a Syk-negative breast cancer cell line markedly inhibited its tumour growth and metastasis formation in athymic mice. Conversely, overexpression of a kinase-deficient Syk in a Syk-positive breast cancer cell line significantly increased its tumour incidence and growth. Suppression of tumour growth by the reintroduction of Syk appeared to be the result of aberrant mitosis and cytokinesis. We propose that Syk is a potent modulator of epithelial cell growth and a potential tumour suppressor in human breast carcinomas.     

An interaction between vinculin and talin

In cultured fibroblasts, microfilament bundles terminate at adhesion plaques (focal contacts), the specialized regions where the cells adhere most tightly to the underlying substrate. Vinculin is a protein concentrated in adhesion plaques and has been suggested as a possible link between the ends of the bundles of actin filaments and the plasma membrane. If vinculin is one protein in a chain of attachment between the bundles of microfilaments and the plasma membrane, it is important to identify other components which interact with vinculin. We have recently discovered a new protein in adhesion plaques which we refer to as talin. Here we show that talin binds to vinculin, which suggests that talin may be involved with vinculin in the attachment of microfilament bundles to the plasma membrane at the adhesion plaques.     

爱因斯坦A-Z

本书是一本传记性著作，记述了20世纪最伟大的科学家之一爱因斯坦的生平。与其他传记体文学不同的是，本书别出心裁的以字母表的顺序，以关键词的方式记录了爱因斯坦的生活、科研、理想等等。从第一个单词大大咧咧的（Absentmindeness），一直到最后一个单词犹太复国主义（Zionism）。每个单词作为一章的标题引出了一段或惊险、或平淡的故事。从本书中读者可以了解爱因斯坦在科学方面的天才想法，可以读到他作为普通人生活的一面——一个可怜的丈夫和父亲，还有他在核武器方面的影响，他创造了相对论却拒绝接受量子力学……