G-substrate is a protein that in humans is encoded by the C7orf16 gene.

The protein encoded by this gene is found primarily in cerebellar Purkinje cells, where it functions as a protein phosphatase inhibitor. The encoded protein is a substrate for cGMP-dependent protein kinase. An allele of this gene was discovered that increases susceptibility to hypercholesterolemia. Two transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Jul 2010].
Function: Inhibits protein phosphatase-2A and protein phosphatase-1.