diff --git a/proto/src/metrics_constants/OWNERS b/proto/src/metrics_constants/OWNERS
new file mode 100644
index 0000000..9c70a5e
--- /dev/null
+++ b/proto/src/metrics_constants/OWNERS
@@ -0,0 +1,3 @@
+yanglu@google.com
+yaochen@google.com
+yro@google.com
diff --git a/proto/src/metrics_constants.proto b/proto/src/metrics_constants/metrics_constants.proto
similarity index 100%
rename from proto/src/metrics_constants.proto
rename to proto/src/metrics_constants/metrics_constants.proto