Its most famous functions, however, are either lipid synthesis or protein production.
One subclass of this organelle features the microsomal P450 oxidase system, which plays a key role in the first-pass effect through the liver. Another variation of this organelle contains the protein calsequestrin, important in regulating skeletal muscle contraction. In neurons this organelle produces many neurotransmitters, stains purple when exposed to aniline, and thus is referred to as Nissl substance. Its most famous functions, however, are either lipid synthesis or protein production. FTP, name this organelle continuous with the nuclear membrane that comes in sarcoplasmic, smooth, and rough varieties.
One subclass of this organelle features the microsomal P450 oxidase system, which plays a key role in the first-pass effect through the liver.
endoplasmic reticulum [accept smooth endoplasmic reticulum before "calsequestrin"]