Integrins in kidney development, function, and disease

Integrins are heterodimeric cell surface receptors that mediate heterophili c cell-cell interactions and interactions between cells and the extracellul ar matrix (Hynes RO. Cell 69: 11-25, 1991). As such, they are involved in m orphogenetic processes during development, as well as in the maintenance of normal tissue architecture in fully developed organs. Integrins are now re cognized to be a large family of receptors, and several different integrins have been demonstrated as being expressed in the developing and adult kidn ey (Korhonen M, Ylkanne J, Laitinen L, and Virtanen I. Development 122: 353 7-3547, 1996; Rahilly MA and Fleming S. J Pathol 167: 327-334, 1992). This review will summarize present knowledge about integrin expression in the de veloping, normal, and diseased kidney and attempt to provide a hypothetical framework for understanding integrin function in the urogenital system. Si nce the last time this area was reviewed (Hamerski DA and Santoro S. Curr O pin Nephrol Hypertens 8: 9-14, 1999), there have been significant publicati ons on the roles of integrins in kidney development and disease. At present , there are many more questions than answers, and integrins present an area where many novel and exciting findings will emerge in the coming years.