The general sign for UP (opposite of down) just points an index finger into
the air.
If you use a double movement this sign can mean "upstairs."
UP:


up till now, ever since, have been...


wake up:


Give up, surrender, sacrifice...


See:
DOWN
You can learn
American Sign Language (ASL) online at American Sign Language University ™
ASL resources by Lifeprint.com © Dr. William Vicars