In this task, you are given a sentence. You are expected to recognize the name of gene or protein. Although there might be several correct answers, you need to write one of them.

Input: Consider Input:  Heterotrimeric guanine nucleotide - binding proteins ( G - proteins ) function as signal transducers for a variety of hormone - coupled enzyme and ion transport systems in eukaryotic cells .

Output: G - proteins


Input: Consider Input:  Indeed , after a single oral dose , the role of the mu - receptor agonist component of the antinociceptive effect of tramadol appears to be minor , with most of the analgesic effect being attributable to nonopioid properties of the parent compound .

Output: mu - receptor


Input: Consider Input:  To probe the inter - relationship between the virion - anchoring function and the oligomerization function , we constructed two serotype 3 ( T3 ) sigma 1 deletion mutants in SV40 expression vectors , one lacking the hydrophobic tail and the hinge , and the other lacking an adjacent region which constituted part of the coiled - coil .


Output: sigma 1