diff --git a/src/base.js b/src/base.js
index 9449858..6e38d43 100644
--- a/src/base.js
+++ b/src/base.js
@@ -12,12 +12,11 @@ import {
 const {Iterator} = Iterable;
 const NOT_SET = {}; // Sentinel value
 
-function Base(rootData, keyPath, updater, deref, size) {
+function Base(rootData, keyPath, store, size) {
   this.size = size;
   this._rootData = rootData;
   this._keyPath = keyPath;
-  this._updater = updater;
-  this._deref = deref;
+  this._store = store;
 }
 
 Base.prototype = {
diff --git a/src/cursor.js b/src/cursor.js
index 0cc90ba..4e57924 100644
--- a/src/cursor.js
+++ b/src/cursor.js
@@ -25,7 +25,7 @@ function cursorFrom(data, keyPath, onChange) {
     atom.watch(onChange);
   }
 
-  return makeCursor(data, keyPath, atom.write.bind(atom), atom.read);
+  return makeCursor(data, keyPath, atom);
 }
 
 exports.from = cursorFrom;
diff --git a/src/utils.js b/src/utils.js
index 7432ed7..c3ff7ec 100644
--- a/src/utils.js
+++ b/src/utils.js
@@ -23,13 +23,13 @@ export function defineRecordProperties(cursor, value) {
   }
 }
 
-export function makeCursor(rootData, keyPath, updater, deref, value) {
+export function makeCursor(rootData, keyPath, store, value) {
   if (arguments.length < 5) {
     value = rootData.getIn(keyPath);
   }
   const size = value && value.size;
   const Cursor = Iterable.isIndexed(value) ? IndexedCursor : KeyedCursor;
-  const cursor = new Cursor(rootData, keyPath, updater, deref, size);
+  const cursor = new Cursor(rootData, keyPath, store, size);
 
   if (value instanceof Record) {
     defineRecordProperties(cursor, value);
@@ -65,15 +65,13 @@ export function subCursor(cursor, keyPath, value) {
     return makeCursor( // call without value
       cursor._rootData,
       newKeyPath(cursor._keyPath, keyPath),
-      cursor._updater,
-      cursor._deref
+      cursor._store
     );
   }
   return makeCursor(
     cursor._rootData,
     newKeyPath(cursor._keyPath, keyPath),
-    cursor._updater,
-    cursor._deref,
+    cursor._store,
     value
   );
 }
@@ -85,7 +83,7 @@ export function updateCursor(cursor, changeFn) {
     deepChange ? Map() : undefined,
     changeFn
   );
-  return makeCursor(cursor._updater(updateFn), cursor._keyPath, cursor._updater, cursor._deref);
+  return makeCursor(cursor._store.write(updateFn), cursor._keyPath, cursor._store);
 }
 
 export function wrappedValue(cursor, keyPath, value) {