In the past 30 years the nuclear pore has been studied, as it is the gatekeeper between nucleus and cytoplasm. It seems to me that it is probably not the only way into the nucleus, and i freely say this from ignorance of nuclear pore biology, but just because in general, it is very unlike “mother nature” to provide only one way to do things.

Their figure Figure 2 from which I have cut and pasted a portion, is just beautiful, looking into the nuclear pore (using SEM) from the cytoplasm of the cell, seeing the nuclear pore basket below, and then looking up from the nucleus of the cell outward, seeing the basket in the center.  What I was struck with is the relative emptiness of the areas between the 8 spokes of the nuclear pore, and immediately thought that the transport of small molecules could just go through there..but I would have to think that the pore would be unlikely to let past 10 nm molecules at the same time as a 39 nm molecule (i think that was documented in some study…  especially since the total central pore unit is 45-50 nm.  I can visualize this wacky wiggling of things being imported and exported through the center of the pore bouncing from side to side, letting smaller molecules go through when possible as larger molecules get transported through.  Reminiscent of the activity in a pinball machine bouncing around.