Table 1. Mechanisms of Creatine transporter modulation.

Molecule/condition	Aspect of CrT modulation	Effect	System	References
Extracellular [Creatine]	Cr uptake	Decrease	L6 myoblasts	[73]
Beta-GPA	Activity	Decrease	HL1 cells	[75]
mTOR and SGK1	CrT trafficking	Increase	Xenopus laevis oocytes expressing CrT cRNA	[76, 77]
Klotho	Max transport rate and transporter on the plasma membrane			[78]
SPAK and OSR1		Decrease		[79]
PGC1α via ERRα	Transcript	Increase	Skeletal muscle cells	[80]
Splice variants SLC6A8C and SLC6A8D	Cr uptake and CrT protein	Increase	3T3 Swiss fibroblasts	[81]
Growth hormone	Transcript	Increase	In vivo in rats post-MI	[82]
AICAR via AMPK and substrate availability	Vmax of Cr uptake and CrT on the plasma membrane	Increase in Vmax	HL1 cardiomyocytes and RNCM	[83]
		Decrease	Kidney proximal tubule cells	[84]
Phorbol esters	CrT activity	Decrease	X. laevis oocytes expressing CrT	[35]
Txnip	Cr uptake CrT protein	Decrease	Mouse fibroblasts overexpressing CrT	[74]
Doxorubicin	Cr uptake and CrT on the plasma membrane	Decrease and removal of CrT from plasma membrane	Rat neonatal cardiomyocytes and HL1 cells	[75]
N-glycosylation at Asn192 and Asn197	CrT function Surface CrT trafficking	Preserves function	HEK293 cells overexpressing CrT	[85]
Phosphorylation at Ser625 Cr supplementation	Cr uptake Phosphorylation at Tyr416	Increase Decrease	Gastrocnemius rat muscle in starvation Gastrocnemius rat muscle in sepsis	[86, 87]