[
Genes Dev,
2003]
Obesity and the occurrence of diabetes are on the rise. Much of this is attributable to a more sedentary lifestyle and high caloric intake in industrialized countries and is a major cause of a variety of health problems. Obesity and diabetes are intimately linked to insulin, which increases glucose uptake in cells and serves as a primary regulator of blood glucose levels. Insulin has been an important target of investigation for decades, as indicated by its sequence determination by Sanger and colleagues in 1955, and is now the subject of renewed interest.
[
Cell,
1996]
Across the animal kingdom, fertilization requires the encounter between a large stationary egg and small motile sperm. To maximize their likelihood of reaching the egg before their competition, sperm are extraordinarily specialized cells, generally consisting of little more than a haploid nucleus, mitochondria to generate energy, and a highly efficient movement engine. Almost all animal sperm are flagellated and seek the egg by swimming quickly through a liquid environment. Nematodes, however, produce sperm that move by crawling along solid substrates. These roundworm sperm extend pseudopods that look and behave like the actin-rich pseudopods of a wide variety of cells ranging from free-living soil amoebae to human white blood cells. The crawling sperm appear by most criteria to be exploiting classic actin-based cell motility, with one important difference: the sperm contain practically no actin (Nelson et al., 1982).