The interaction of PMP and Six Sigma is basically to execute the project effectively
PMBOK talks about five process area in a project viz-
1. Initiation
2. Planning
3. Execution
4. Monitoring And Control
5. Closure

Also, it talks about ten knowledge areas viz-
1. Integration Management
2. Scope Management
3. Time Management
4. Cost Management
5. HR Management
6. Risk Management
7. Stakeholder Management
8. Communication Management
9. Procurement Management
10. Quality Management

Six Sigma PMP Integration is a good way forward for all Lean Six Sigma Professionals.
When you are doing a six sigma project or designing the six sigma framework or PMO fair bit of PMBOK (Project Management body of Knowledge) can be used.

PMBOK for instance talks about five process area in a project viz-
1. Initiation
2. Planning
3. Execution
4. Monitoring And Control
5. Closure

Also, it talks about ten knowledge area viz-

1. Integration Management
2. Scope Management
3. Time Management
4. Cost Management
5. HR Management
6. Risk Managemnt
7. Stakeholder Managemnt
8. Communication Managment
9. Procurement Managemnt
10. Quality Management

From where I see, Project Management of a Lean Six Sigma Project is a critical success element and should one use the PMBOK, the challenges could be identified well in advance and overcome.
The 47 activities as outlined in the PMBOK which fall under the 5 process groups and 10 Knowledge areas lays down a broad skeleton of activities that could make the project logical, hence more prone to success.
The OPAs (Organizational Process Assets) and EEFs (Enterprise Environmental Factors) as necessitated by PMBOK seems to be a logical input for any organizational Six Sigma initiative.
Organizations for better management of LSS initiatives must set up some framework which shall bring in standardization and save time. Such a framework and a management body like a Six Sigma PMO could learn extensively from the same. A SS PMO could help the organization in multiple ways namely-

1.Creation & maintenance of knowledge assets like SOPs, W.I, Tools, template, checklist (OPA – Organization process asset creation) & their upkeep.

2. PMO could serve as a escalation point or go to people in case of some crisis, confusion or dispute.

3. Auditing the project at defined toll gates for completeness and sanity.

4. Knowledge & Lessons Learnt Management

5. Idea generation mgmt.

6. Setup of measurement system in the organization.

And while you intend to setup the Six Sigma PMO or whatever else you can this, PMBOK will be extremely useful and make the entire effort easier.

To be Continued…