Bap2, branched-chain amino acid permease; CS, cigarette smoke; CSE, cigarette smoke extract; ChIP, chromatin immune precipitation; Cigarette smoke; E, glutamic acid; Emphysema; EtBr, ethidium bromide; F, phenylalanine; H & E, hematoxylin and eosin; H, histidine; I, isoleucine; K, lysine; L, leucine; LAT1; Lat1, L-type amino acid transporter 1; Leucine; M, methionine; Mad1, Max dimerization protein 1; N, asparagine; PCR, polymerase chain reaction; R, argnine; ROS, reactive oxygen species; S, serine; T, threonine; TUNEL, terminal deoxynucleotidyl transferase dUTP nick end labeling; Tat1, tyrosine and tryptophan amino acid transporter 1; V, valine; W, tryptophan; Y, tyrosine; YCM, yeast complete media; mTOR; mTOR, mammalian target of rapamycin