The phrase "a second receptor for" is correct and usable in written English.
It can be used in scientific or medical contexts when discussing biological receptors and their functions or interactions.
Example: "Researchers have discovered a second receptor for the hormone, which may play a crucial role in regulating metabolism."
Alternatives: "an additional receptor for" or "a secondary receptor for".
Recently, CXCR7 was identified as a second receptor for CXCL12.
CXCR7 is a second receptor for CXCL12 that binds this chemokine with greater affinity than CXCR4.
Another GPCR, CXCR7, has been identified as a second receptor for SDF-1α.
However, the recent identification of RDC1/CXCR7 as a second receptor for CXCL12 has challenged this view, and we now need to determine the respective contributions of CXCR4 and CXCR7 to the homeostatic and pathological activities of CXCL12 [ 47- 49].
The efforts have already yielded one major find: a third receptor for histamine, a chemical released in the body in response to stress, inflammation and allergies.
A third receptor for adiponectin, T-cadherin, expressed on vascular endothelial cells and smooth muscle, is a receptor for hexameric and HMW adiponectin [ 17].
In addition, BAFF binds to BAFF receptor found mainly on B cells, plasma cells, and some subsets of T cells [ 15, 16], while APRIL interacts with heparin sulfate proteoglycans, which likely constitutes a third receptor for APRIL [ 17].
While measuring the effects of estriol on GPR30 in TNBC cell lines we were aware that besides ERα and GPR30 (GPER) there is a third receptor for estrogens, ERβ, in many different cell types.
A second receptor needed for the entry of HIV into cells was identified and named "fusin" (CXCR4) because it enables certain strains of HIV to fuse with and enter immune cells called T cells.
We have identified a role for a second receptor kinase signaling pathway - the ER pathway - in WUS regulation, and therefore in SAM and FM size regulation, that acts independently of the CLV signaling pathway.
CXCR7 is a recently described second receptor for CXCL12 and was shown to promote lung cancer growth in vivo (Miao et al, 2007) but this receptor might rather modulate CXCR4-mediated responses than act as an independent CXCL12 receptor (Hartmann et al, 2008).
