Contents

14 February 1992
Vol 255, Issue 5046

About The Cover

A cluster of the sea star Pisaster ochraceus on a beach of the Pacific Rim National Park, Vancouver Island, British Columbia. The oocytes from this echinoderm have been used as a source of the mitogen-activated protein (MAP) kinase p44mpk, which is now shown to be phosphorylated and activated by the lymphocyte protein tyrosine kinase p56lck. See page 853. [Photograph by Peter Thomas]