[AntonioLao]

The answers are yes and no. When electrons move at relativistic speeds they gain mass. Subsequently, when they slowed down, they lose mass. However, no electron can ever lose more than its rest mass. Therefore it is logical to surmise that two kinds of mass exist: potential and kinetic.

The potential mass depends on intrinsic attributes while the kinetic mass depends on extrinsic attributes. One intrinsic attribute would be the amount of space-time quanta found inside the particle, which for an electron, implies it is composite even though experimentally, it is a point particle (with no hope of ever finding any substructure). An extrinsic attribute would be its speed in neutral space-time.

If the electron is composed of space-time quanta, how many would it have? Imagine that it has a shape like a cube with 6 faces, 8 vertices, and 12 edges, satisfying Euler’s formula for polyhedrons especially for the 5 regular Platonic solids. Each vertex is associated with 3 edges to form a single invariant directional property. Therefore, there are 8 irreducible properties. Their symmetries are similar to a gauge symmetry of SU(3) implying that gluons might just be these directional properties.
Having a complete set of these 8-directional properties is what makes a real particle real. On the other hand, missing one is more than enough to change a real particle into virtual particle.

The potential mass is a result of lopsided intrinsic distributions (spontaneous symmetry breaking) of these 8 properties. Since space-time is uniformly distributed at every dimensional level, the effect of an electron moving through space-time changes the uniform distributions hence all moving particles subsequently acquire kinetic mass as well.