THE INTEGRIN ALPHA-4-BETA-1 AND ITS COUNTER-RECEPTOR VCAM-1 IN DEVELOPMENT AND IMMUNE FUNCTION

The integrin alpha 4 beta 1 and its counter receptor vascular cell adh esion molecule-1 (VCAM-1) mediate well-described cell-cell interaction s that are critical for immune function. However, these receptors also mediate cell-cell interactions that are important for skeletal muscle differentiation. We have found that contrasting transcriptional mecha nisms control their patterns of expression in the immune system and in muscle. Recent studies indicate that alpha 4 beta 1 and VCAM-1 are al so expressed in a number of developing tissues, implying that these re ceptors have a general role in facilitating cell-cell interactions dur ing development.