Functional significance

Interestingly, there are many proteins with two domains that show a very clear hinge-bending motion with an obvious functional significance. Such domains have often been reported in the literature, but were never detected on an automated basis. 

Figure 13.24 Six subfamilies of receptor tyrosine kinases involved in cell growth and differentiation. Only one or two members of each subfamily are indicated. Note that the tyrosine kinase domain is interrupted by a "kinase insert region" in some of the subfamilies. The functional significance of the cysteine-rich and immunoglobulin-like domains is unknown.

There is abundant experimental evidence suggesting that many (if not most) GPCRs exist as homodimers and/or heterodimers [4]. The functional significance of dimers and their role in G protein activation remains to be determined for most GPCRs. Experimental evidence suggests that dimers may play roles in processing and maturation of newly synthesized receptor protein. Heterodimers may contribute to pharmacologic... 

Moreover, there exist polymorphic MOP variants. An Asn40Asp polymorphism has been found with a high abundance in the Caucasian and Asian population. This receptor variant is less expressed in the brain and carrier of this polymorphism appears to need more opioids for analgesic treatment. There are many additional MOP polymorphisms with unknown functional significance. In spite of many studies there appears to exist no significant association of polymorphisms in the MOP gene and drug addiction [5]. 

According to the NC-IUPHAR Subcommittee on Opioid Receptois it was proposed to term ORL-1 recqrtor as NOP receptor [1]. The human NOP receptor gene encodes a protein of370 amino acids. Splice valiants have been found in the human and mouse NOP recqrtor with no known functional significance. NOP receptors are widely distributed throughout the brain and in the spinal cord. They are also present in immune cells. A functional role for N/OFQ has been proposed in nociception, locomotoric activity, reward, stress, and immunomodulation. 

More recent analysis of tissue specific gene deletions showed that the Cav1.2 channel is involved in a wide variety of function including hippocampal learning, insulin secretion, intestine and bladder motility. Further analysis will be required to unravel the functional significance of voltage-dependent calcium channels for specific cellular functions. 

Second, although typical neuroleptics produce depolarisation block of both A9 and AlO neurons, the atypical neuroleptics only induce it in AlO neurons (Chiodi and Bunney 1983). So after an atypical neuroleptic the A9 neurons of the nigrostriatal tract remain functional, which would explain why EPSs are not seen. Another difference is seen with the expression of an immediate-early gene, c-fos, and although its functional significance is not clear, typical neuroleptics induce its protein production in both the striatum and nucleus accumbens while the atypicals only achieve it in the accumbens. 

Mineralization and immobilization in the rhizosphere are processes that are probably suitable to enable us to estimate ecosystem performance—e.g., productivity, stability, resilience. To properly answer this question, we should understand how differences in plant species may affect below-ground subsystems and what is the functional significance of diversity of. soil organisms. 

Schwenk K. (1985). Occurrence, distribution, and functional significance of taste buds in lizards. Copeia, 91-101. 

Soucek G., Breit S., Konig H. and Liebich H. (1999). Functional significance of musculature of the external nose in swine (Sus scrofa f. domestica). Anat Histol Embryol 28, 307-314. 

The organization of chemokine families based on the cysteine sequence has functional significance. Some human chemokines can compete for binding and activation of receptors with other intrafamily chemokines. This raised the possibility that significant structural differences in chemokine-receptor interactions... 

The Functional Significance of Dimerization Is More Unclear among... 

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