The function of GPHB5 (glycoprotein hormone subunit beta 5, ENSG00000179600) is as follows. Functions as a heterodimeric glycoprotein hormone with GPHA2 able to bind and activate the thyroid-stimulating hormone receptor (TSHR), leading to increased cAMP production. Plays a central role in controlling thyroid cell metabolism. {ECO:0000269|PubMed:12045258, ECO:0000269|PubMed:16210345}.