Protools can not use the VST format in it's native form, no.
"Rewire" is a program to program link developed by Propellerheads. It takes the place of hardware wiring (MIDI cables and audio cables) between two programs. It works on a "host"/"client" sort of basis, and Pro Tools is a rewire "host". Other programs, such as Propellerheads Reason, Sony Acid, Ableton Live can all function as rewire "clients". Linking programs this way also links the transports of the pograms; hit start in the rewire host and the client starts at the same location and plays along in sync. Some rewire clients have the cabablities to run VST instruments. So, you could technically run VSTi (instrument) plugins in this fashion, say with Ableton Live rewired to PT and a VSTi loaded in Live. With the current rewire specification, MIDI and audio only flow in one direction (MIDI out from the host to the client, and audio in from the client to the host), so unless the audio you are trying to process resides on the client, you will only be able to use VSTi, not regular audio manipulation VST, using rewire.
The more popular way to run VSTi and other VST plugs in Protools is by using the
VST-RTAS adapter from FXPansion. This handy (and well worth the money IMHO) piece of software "wraps" almost any VST plugin so that it can be used within protools in it's native RTAS plugin format.