diff --git a/packages/google-cloud-private-ca/setup.py b/packages/google-cloud-private-ca/setup.py
index c75d47209398..74cf8bf34047 100644
--- a/packages/google-cloud-private-ca/setup.py
+++ b/packages/google-cloud-private-ca/setup.py
@@ -43,8 +43,8 @@
     include_package_data=True,
     install_requires=(
         "google-api-core[grpc] >= 1.32.0, <3.0.0dev,!=2.0.*,!=2.1.*,!=2.2.*,!=2.3.*,!=2.4.*,!=2.5.*,!=2.6.*,!=2.7.*",
-        "proto-plus >= 1.15.0, <2.0.0dev",
-        "protobuf >= 3.19.0, <4.0.0dev",
+        "proto-plus >= 1.22.0, <2.0.0dev",
+        "protobuf >= 3.19.0, <5.0.0dev",
     ),
     python_requires=">=3.7",
     scripts=[
diff --git a/packages/google-cloud-private-ca/testing/constraints-3.7.txt b/packages/google-cloud-private-ca/testing/constraints-3.7.txt
index 317c02ddaa88..51901fbcf804 100644
--- a/packages/google-cloud-private-ca/testing/constraints-3.7.txt
+++ b/packages/google-cloud-private-ca/testing/constraints-3.7.txt
@@ -6,5 +6,5 @@
 # e.g., if setup.py has "foo >= 1.14.0, < 2.0.0dev",
 # Then this file should have foo==1.14.0
 google-api-core==1.32.0
-proto-plus==1.15.0
+proto-plus==1.22.0
 protobuf==3.19.0