Notch-mediated juxtacrine signal between adjacent cells.
This  <a href="https://en.wikipedia.org/wiki/Vector_images" class="extiw" title="w:Vector images">vector image</a> was created with <a href="https://en.wikipedia.org/wiki/Adobe_Illustrator" class="extiw" title="w:Adobe Illustrator">Adobe Illustrator</a>.
<a href="//commons.wikimedia.org/wiki/File:Notchccr.gif" class="image"><img alt="Notchccr.gif" src="https://upload.wikimedia.org/wikipedia/commons/thumb/f/f2/Notchccr.gif/100px-Notchccr.gif" decoding="async" width="100" height="93" srcset="https://upload.wikimedia.org/wikipedia/commons/thumb/f/f2/Notchccr.gif/150px-Notchccr.gif 1.5x, https://upload.wikimedia.org/wikipedia/commons/thumb/f/f2/Notchccr.gif/200px-Notchccr.gif 2x" data-file-width="500" data-file-height="464"></a><br>Graphic: National Institute of Health.  U.S. <a rel="nofollow" class="external free" href="https://ccr.cancer.gov/staff/images/1372_Fortini_178.gif">http://ccr.cancer.gov/staff/images/1372_Fortini_178.gif</a>