I am a citizen of Japan and a permanent resident of US. I live in US (sleep in US every night) and commute to work in Canada, having a valid Canadian work permit. I am now considering applying for US citizenship. If I do, I expect to become a US citizen before my work permit expires, and will lose my Japanese citizenship at the same time (as the Japanese law on nationality says that acceptance of another nationality implies loss of Japanese citizenship). I am wondering what would happen to my work permit then. I would appreciate your help.