Umami is one of five basic tastes along with sweetness, sourness, bitterness and saltiness. We can taste umami because of heteronomy (Hets): specifically, the combination of two receptors to form one action. Today’s heteronomy update explained the umami Hets like this:
"Taste T1 receptors are obligate Hets: ‘T1R3 acts as an obligate partner in T1R1/T1R3 and T1R2/T1R3 heterodimers, which sense umami or sweet, respectively.’"
Pharmaceutical cannabinoid research has regressed on the subject of Hets; they see evidence of cannabinoid Hets yet can’t synthetically reproduce them. The update warns: “in a sense, the field is going backward instead of forward.”
Basic Pharmacological and Structural Evidence for Class A G-Protein-Coupled Receptor Heteromerization
Frontiers in Pharmacology ~ 31 March 2016
Cell membrane receptors rarely work on isolation, often they form oligomeric complexes with other receptor molecules and they may directly interact with different proteins of the signal transduction machinery. For a variety of reasons, rhodopsin-like class A G-protein-coupled receptors (GPCRs) [Cannabinoids] seem an exception to the general rule of receptor–receptor direct interaction. In fact, controversy surrounds their potential to form homo- hetero-dimers/oligomers with other class A GPCRs; in a sense, the field is going backward instead of forward. This review focuses on the convergent, complementary and telling evidence showing that homo- and heteromers of class A GPCRs exist in transfected cells and, more importantly, in natural sources. It is time to decide between questioning the occurrence of heteromers or, alternatively, facing the vast scientific and technical challenges that class A receptor-dimer/oligomer existence pose to Pharmacology and to Drug Discovery.
*Next Up: The Union 2016 summer series continues on Saturday 27 August with part 9, Johnny Reb and Gus Kotka Nowhere Nobody Home.
Posted by Bryan W. Brickner